Calorie Calculator for Weight Maintenance
"How much should I eat?" is a question with a real answer, one that starts with maths, not vibes. This free calorie calculator for weight maintenance uses the Mifflin-St Jeor equation, the formula dietitians trust most, to estimate your BMR and TDEE with your activity level from your age, gender, height and weight. Then it turns those numbers into practical daily targets for gentle fat loss, faster fat loss, or steady muscle gain. Estimates your TDEE from age, sex, weight, height and activity level, then sets calorie targets for losing, maintaining or gaining weight.
Last updated: October 22, 2026
Your result
The formula
BMR (men) = 10 × weight + 6.25 × height − 5 × age + 5BMR (women) = 10 × weight + 6.25 × height − 5 × age − 161TDEE = BMR × activity factorFat loss target = TDEE − 500 kcal per dayMuscle gain target = TDEE + 300 kcal per day
A worked example
A 30-year-old man, 178 cm and 75 kg, moderately active: BMR = 10×75 + 6.25×178 − 5×30 + 5 = 1,717.5 kcal/day. Multiplied by the 1.55 activity factor, his maintenance (TDEE) is about 2,662 kcal/day, so gentle fat loss lands near 2,412 and steady muscle gain near 2,962.
More about the Calorie Calculator
From BMR to daily calorie needs
The full calculation, shown once, so you trust the number. A 30-year-old man, 178 cm, 75 kg, moderately active: BMR = 10×75 + 6.25×178 − 5×30 + 5 = 1,717.5 kcal/day. Activity factor 1.55 → TDEE ≈ 2,662 kcal/day maintenance. Gentle fat loss (−250): ≈ 2,412. Standard fat loss (−500): ≈ 2,162. Steady muscle gain (+300): ≈ 2,962. Five numbers, one coherent plan, and it shows why "eat 1,200 calories" advice would be nonsense for this person: that is 500 below his BMR, the floor his body needs just to exist.
How to use these targets in real life. Pick the activity level that matches a typical week, not your most heroic one, overestimating activity is the #1 reason targets feel "wrong". Run the gentle deficit first; you can always deepen it. Weigh yourself daily but compare weekly averages, not day to day noise. After 2 to 3 weeks with no movement, adjust intake by 200 kcal, the equation got you close, your body's own data finishes the job.
Sizing your deficit and tracking honestly
A few things that matter more than the formula. Protein first: it preserves muscle in a deficit and keeps you full, aim for roughly 1.6 to 2.2 g per kg of body weight. Sleep 7+ hours; short sleep raises hunger hormones measurably. Do not cut below your BMR, the calculator shows it so you can see the floor. And expect the first week's drop to be mostly water; judge the plan from week three onward.
The honest caveats: these are estimates for healthy adults, not medical advice, talk to a doctor or dietitian before big changes, especially with any medical condition, pregnancy, or history of disordered eating. The equation does not know your body composition, thyroid status or medications. It is the best free starting point available, and your scale over the coming month is the calibration it cannot do for you.
Calories by activity: running, cycling, swimming
A rough rule: running burns about 1 kcal per kg of body weight per kilometre, an 80kg runner burns roughly 80 kcal per km. Cycling at moderate effort is roughly half that per kilometre; swimming freestyle sits between the two per minute of effort.
Speed matters less than people think for running, distance dominates. For cycling, speed matters a lot because of air resistance. For swimming, technique swamps everything: form is the biggest variable in the pool.
Use the activity picker in the calculator for estimates, and treat fitness tracker numbers as approximate (often ±20%). They are estimates, not lab measurements.
What your BMR actually measures
The maths, shown once: a 30-year-old man, 75 kg, 178 cm. BMR = 10×75 + 6.25×178 − 5×30 + 5 = 1,717.5 kcal/day just to exist. Now the activity multipliers: sedentary (×1.2) → ≈2,061; lightly active (×1.375) → ≈2,362; moderately active (×1.55) → ≈2,662; very active (×1.725) → ≈2,963; extra active (×1.9) → ≈3,263. Same body, a 1,200 kcal spread, activity level does more work in this calculation than most people expect, which is why picking it honestly matters.
How to use your number. Your BMR is the baseline your body runs on at rest, treat it as a reference, not a target. Your TDEE (the activity row matching a typical week) is the budget: maintenance lives here, weight loss lives 300 to 500 below it, muscle gain 250 to 500 above. Pick the activity row for your normal life, not your best week, a desk worker who trains three times a week is "moderately active", not "very". Overestimating activity is the classic reason calorie targets feel wrong.
From BMR to real daily burn
A few tips for accuracy. Enter your honest weight, the equation is sensitive to it, and vanity inputs produce vanity outputs. Re calculate after every 5 kg of weight change; your BMR drops as you get lighter, which is the physiological reason behind plateaus. In imperial units, double check the pounds and inches entries, unit mix ups are the most common error. And pair this with our calorie calculator when you are ready to turn your TDEE into a weight goal plan.
The fine print: the Mifflin-St Jeor equation is the most validated formula for the general population, but it works from age, sex, height and weight. It cannot see your muscle mass, thyroid, medications or history of dieting. Expect it to land within ~10% for most people; at the extremes it drifts further. It is the best free starting point in existence, and your body's actual response over the next month is the calibration no formula can replace.
What macros actually are
Protein, carbs and fat are the three nutrients that carry calories, everything on your plate is some mix of the three. Each one pulls its weight: protein builds and protects muscle and tissue, fat keeps hormones humming, and carbs fuel training and everyday life.
How the calculator splits your calories
Protein gets set first, from your body weight and goal, 1.6, 2.0 or 2.2 grams per kilo. Fat then takes its slice of your calories (25% by default), and carbs fill whatever energy is left. Anchors first, flexible macro last.
Cutting, maintaining, or bulking
Cutting keeps protein high so you hold onto muscle while calories drop. Maintaining balances all three for steady weight. Bulking leans on extra carbs to fuel growth. Same tool, three different strategies, the goal preset handles the switching.
Setting your calorie target
Type in a target you already trust, or let the tool estimate one from your activity level. One caveat: the split is only as good as the calorie number it is built on, feed it a shaky target and you get a precise looking plan that is wrong in all the right proportions.
Adjusting the defaults
Prefer fattier foods or train at high volume? Nudge the fat percentage up. Cutting hard? Bring it down. Very active? Bump the protein factor a touch. The tool recalculates instantly, so play around, the defaults are a starting point, not a prescription.
Using your results day to day
Treat protein as the one macro to hit closely. It is the one most tied to keeping muscle and staying full. Carbs and fat can flex around it day to day without derailing you. And recalculate whenever your weight shifts a few kilos or your goal changes; stale targets quietly stop working.
Keto macros: how to set them
Standard ketogenic macros run roughly 70 to 75% fat, 20 to 25% protein and 5 to 10% carbs. On a 2,000-calorie day that is about 155 to 165g fat, 100 to 125g protein and 25 to 50g net carbs.
Protein is the lever most people get wrong: too little and you lose muscle alongside fat. Set protein from lean mass first, then fill the remaining calories with fat.
Net carbs (total carbs minus fibre) is the number that matters for ketosis, 20 to 30g net is the common starting zone. Track net, not total, or you will under eat vegetables for no reason.
A complete worked split: 90 kilograms cutting on 2,200 calories
Suppose a 90 kg lifter is cutting on a 2,200 kcal target. Following the calculator’s order of operations, protein is set first from body weight: at the 1.6 g per kilogram cutting factor, that is 144 grams, worth 144 × 4 = 576 kcal. Fat takes 25 percent of the budget next, 550 kcal, which at 9 kcal per gram is 61.1 grams. Carbs absorb whatever remains: 2,200 − 576 − 550 = 1,074 kcal, divided by 4 to give 268.5 grams.
Sanity check the finished split before you trust it. The calories add back exactly, 576 + 550 + 1,074 = 2,200, and expressed as shares of the day, the split is roughly 26 percent protein, 25 percent fat, and 49 percent carbohydrate. That shape is typical of a moderate cut: protein high enough to defend muscle at this body weight, fat held at a floor that keeps meals satisfying, and carbs taking the strain because they are the only lever left once the other two are fixed.
Where tidy macro maths meets messy real food
Food labels round more aggressively than your targets do. Grams are rounded to whole numbers and calories to the nearest ten on many labels, so a day assembled from five packaged foods can quietly drift 50 to 100 kcal from the figures you logged, in either direction. Weighing staples yourself removes most of the error, because the same rounding does not apply to your own scale. The other classic mismatch is cooked versus raw: rice roughly triples in weight as it absorbs water, while meat loses water and shrinks, so a per-100-gram figure only works if you match the state the food was in when it was measured.
One energy source sits outside the three macros entirely: alcohol, at about 7 kcal per gram. A drink can add a couple of hundred calories that no protein, fat, or carb target budgeted for, which is why a week of perfect macro adherence can still stall when weekends go uncounted. You do not need a separate alcohol macro, just treat drinks as coming out of the carb allowance for that day, and the arithmetic of the split stays honest.
How the daily target is actually set
The calculator works from grams of protein per kilogram of body weight per day, the unit sports nutrition research uses, because protein needs scale with the size of the body they are maintaining. Your goal picks the band: 1.2 to 1.6 g/kg for maintenance, 1.6 to 2.2 g/kg for losing weight or building muscle. Your activity level then slides you within that band, from the low end if you are mostly sedentary to the high end if you train hard.
That is why two people can get very different answers from the same tool. A 60 kg office worker maintaining weight lands around 72 to 96 g a day; a 90 kg lifter cutting weight lands around 144 to 198 g. Same calculator, same logic, the inputs do the work, which is exactly the point.
Why your goal changes the number
When you are losing weight, protein does quiet double duty: it keeps you fuller on fewer calories, and it protects the muscle you already have while the fat comes off. That is why the weight loss band sits higher than maintenance, dieting bodies are more inclined to burn muscle, and protein is the main nutritional brake on that process.
For muscle building, protein is the raw material, but more is not infinitely better. Research consistently shows the benefit plateaus around 1.6 g/kg for most lifters; going to 2.2 g/kg covers hard gainers and very high training volumes. Beyond that, extra protein mostly becomes expensive calories.
Activity level matters more than people think
Training damages muscle fibers; protein repairs them. The more frequent and intense the training, the more repair material you need, which is why the calculator nudges athletes toward the top of their band and sedentary people toward the bottom. A marathon runner and a desk worker at the same weight genuinely need different amounts.
Be honest with this input and it pays off: picking \"athlete\" when you walk twice a week inflates your target by 20 to 30 g a day for zero benefit. Stuck between two levels? Pick the lower one. You can always eat a little more, but an intimidating target you ignore helps nobody.
Splitting protein across your meals
A daily target of 150 g sounds abstract; "about 38 g per meal across four meals" is a plan. Your body uses protein most efficiently in doses of roughly 25 to 40 g per meal, beyond that, the muscle building signal per gram starts to flatten. Front loading 100 g at dinner and skipping protein at breakfast wastes much of the day's potential.
The calculator's per meal figure assumes four meals, which suits most schedules. If you eat three larger meals, divide the daily target by three instead, the daily total is what matters most, and the per meal split is about making that total practical rather than perfect.
Foods that make the grams easy
Hitting 120 to 150 g a day is straightforward once you anchor each meal with a protein source: a chicken breast (about 40 g), a cup of Greek yogurt (about 20 g), two eggs (about 12 g), a can of tuna (about 30 g), a cup of lentils (about 18 g) or a scoop of whey (about 25 g). Two anchored meals plus a protein rich snack usually gets most people to their target.
Plant based eaters can absolutely hit these numbers, soy, tempeh, lentils, chickpeas, quinoa and pea protein powders all count, but it takes slightly more planning, since plant proteins are less concentrated per bite. Variety across the day covers the amino acid picture without any spreadsheet gymnastics.
When this estimate needs a professional
This calculator is a general guideline for healthy adults planning meals. It is not medical advice. Protein needs shift meaningfully during pregnancy and breastfeeding, after 65 (older adults often need more to protect muscle), and with kidney disease, where high protein can be genuinely harmful rather than merely wasteful.
If any of those apply, or if you are managing diabetes, gout or a prescribed medical diet, take the calculator's number as a conversation starter with your doctor or dietitian, not as the final answer. For everyone else, it is a solid, evidence aligned starting point.
How to use the Calorie Calculator
- Enter your age, gender, height and weight honestly, the equation is sensitive to all four.
- Pick the activity level that matches a typical week, not your hardest week.
- Press Calculate and read your maintenance calories first. That is your anchor number.
- Choose a goal row (fat loss or muscle gain), treat it as a daily target, and adjust after 2 to 3 weeks of real results.
BMR questions
What does BMR actually measure?
The energy your body burns at complete rest over 24 hours, no movement, no digestion, just staying alive. For most people that is 60 to 70% of all calories burned in a day, which surprises everyone: you burn most of your calories doing absolutely nothing. Activity and exercise are the smaller slice.
Should I eat below my BMR to lose weight faster?
Think of BMR as a reference point, not a medical rule. Most guidelines suggest planning weight loss from your TDEE (BMR × activity) with a moderate 300 to 500 kcal deficit, rather than anchoring on BMR itself. Very low intakes can cost you muscle and energy, and are worth discussing with a professional if you have any health condition. The calculator shows your BMR so you can see the baseline your total burn builds on, and so you can keep your target comfortably above crash diet territory.
How accurate is this versus a lab test?
Within about 10% for most people. A lab measures your real metabolic rate with indirect calorimetry, analysing your breath, while the calculator estimates from population data. Close enough for meal planning. The exceptions: thyroid conditions, pregnancy and elite athletes can all push the real number meaningfully off the formula, so treat it as a starting point there.
Which is more accurate: Mifflin-St Jeor or Harris-Benedict?
This calculator uses the Mifflin-St Jeor equation: 10 × weight in kg, plus 6.25 × height in cm, minus 5 × age, plus 5 for men or minus 161 for women. In validation studies it has tested slightly more accurate for today's adults than the 1919 Harris-Benedict formula, though the two usually agree within about five percent. Either way, treat the number as a well grounded estimate, only a lab test measures your true metabolic rate.
What is the Mifflin-St Jeor formula?
For men: BMR = (10 x weight in kg) + (6.25 x height in cm) - (5 x age) + 5. For women: BMR = (10 x weight in kg) + (6.25 x height in cm) - (5 x age) - 161. It is the equation the Academy of Nutrition and Dietetics recommends for clinical practice, and it is the one this calculator uses.
What is the difference between BMR and RMR?
BMR is measured under strict lab conditions: fully rested, fasted, lying still in a dark room. RMR (resting metabolic rate) is measured under looser conditions and runs about 10% higher, because it includes small things like sitting up and digesting. In practice the two get used interchangeably, but a lab RMR test will usually read a bit higher than this calculator's BMR.
How often should I recalculate my BMR?
Whenever your inputs change meaningfully: after losing or gaining about 5 kg, after a birthday that moves you into a new decade, or when your goal shifts from losing to maintaining to gaining. Checking every 2 to 3 months during active weight change keeps your calorie targets honest instead of drifting.
What factors affect my BMR?
Age, sex, weight, height and muscle mass do most of the work: BMR falls as you age and rises with more lean muscle, which is why two people at the same weight can have very different numbers. Illness, stress, hormones and long stretches of very low calorie dieting move it too, another reason a calculator gives a planning estimate rather than a lab measurement.
How do I calculate my BMR?
Use the Mifflin-St Jeor formula, the most accurate for BMR. Men: 10 × weight(kg) + 6.25 × height(cm) − 5 × age + 5. Women: 10 × weight(kg) + 6.25 × height(cm) − 5 × age − 161. This gives the calories you burn at complete rest, before any activity.
Macro questions
Why does the calculator use 2.0 g/kg of protein?
Most nutrition coaches set protein by body weight: about 1.6 g/kg for cutting, 2.0 g/kg for maintaining, and 2.2 g/kg for lean bulking. These numbers keep you near the top of the evidence based range for active people without turning every meal into a protein challenge.
Why are carbs calculated as the remainder instead of a fixed number?
Because calories are a budget. Once protein is fixed for your goal and weight, carbs are the flexible filler. This keeps protein protective of muscle, fat adequate for hormones, and carbs supplying whatever energy remains. If you prefer higher fat or keto style eating, the calculator lets you override the fat percentage first.
Is 25% of calories from fat the right amount?
Twenty five percent of calories from fat is a middle ground default that supports hormone health and satiety for most people. Athletes doing high volume training often raise it, while low fat cutters may drop it, both are fine, which is why the tool lets you adjust it.
How accurate are these macro targets?
The gram results are exact math, but they're still estimates, not medical advice. Activity trackers overestimate burn, food labels can be off by 10% or more, and protein needs vary with training. Treat the targets as a starting point and adjust based on real progress over 2 to 3 weeks.
Do I need to hit my macros exactly every day?
For most people, no. If you stay within your calorie target, small shifts between carbs and fat have a minor effect on results. The one macro worth hitting closely is protein, that's the one most directly tied to muscle retention and fullness.
Should I recalculate macros as I lose or gain weight?
You can, but it's not required for the split to work. If your weight trends the wrong way after a couple of consistent weeks, adjust calories by 100 to 200 rather than blaming the macro ratio. The tool recalculates instantly if you change your target.
Can I use this calculator in pounds instead of kilograms?
Yes, the same formulas apply, you just enter your weight in pounds and the calculator converts it to kilograms first (1 kg = 2.20462 lb). Everything after that, including the worked example numbers, runs on kilograms.
What's the best macro split for cutting versus bulking?
Add or subtract roughly 300 to 500 kcal from maintenance and keep protein at the higher end (around 2.2 g/kg) when cutting to protect muscle. The calculator's goal presets handle this automatically, including the aggressive cut protein bump.
Does tracking macros work better than just counting calories?
For body composition, yes. Calories decide whether you lose or gain weight, but macros decide what that weight is, high protein during a cut protects muscle, and adequate carbs fuel hard training. If you only watch calories, you can hit your target while quietly losing muscle you wanted to keep.
What are macros in dieting?
Macros are the three macronutrients that supply calories: protein (4 cal/g), carbohydrates (4 cal/g) and fat (9 cal/g). Tracking them, not just total calories, helps you lose fat while keeping muscle or gain muscle without excess fat.
Protein intake questions
What is a good daily protein target?
It depends on your weight, goal and activity: roughly 1.2 to 1.6 g per kg of body weight for maintenance, and 1.6 to 2.2 g per kg when losing weight or building muscle. Enter your details above and the calculator gives you your personal number in grams, for example, a 75 kg person building muscle lands around 150 g a day.
How is my protein target calculated?
Your weight in kilograms gets multiplied by a grams per kilo factor matched to your goal, 1.2 to 1.6 for maintenance, 1.6 to 2.2 for fat loss or muscle gain, then nudged up or down within that band by your activity level. Imperial weights convert to kilograms first (lb ÷ 2.20462), so the same science holds in both unit systems.
How much protein do I need to build muscle?
Around 1.6 to 2.2 g per kg per day, spread across 3 to 5 meals. Research shows muscle building benefits plateau near 1.6 g/kg for most lifters; the top of the range covers very high training volumes. Training progressively and sleeping enough matter at least as much as the extra grams.
How much protein should I eat per meal?
Roughly 25 to 40 g per meal is the sweet spot where your body uses protein most efficiently for muscle maintenance and growth. Divide your daily target by your number of meals, the calculator shows a four meal split, so for three meals just divide the daily total by three.
Is too much protein bad for your kidneys?
For healthy people, research to date shows no evidence of kidney harm from high protein intakes up to about 2.2 g/kg. The concern is real, though, for anyone with existing kidney disease, if that's you, don't follow a high protein target without your doctor's sign off.
Can I hit my protein target without meat?
Yes, with a bit of planning. Dairy, eggs, soy, tempeh, lentils, chickpeas, quinoa and protein powders all contribute meaningfully, a cup of lentils has about 18 g, and soy is a complete protein. Mixing sources across the day covers all essential amino acids without any meat at all.
Should I eat the same protein on rest days?
Keep it steady. Your muscles keep repairing for 24 to 48 hours after training, so rest days are when much of the rebuilding actually happens. Cutting protein on rest days saves barely any calories and slows recovery. Consistency across the week beats precision on any single day.
Do I really need protein powder, or can I reach my target with food alone?
Food alone works for most people. A chicken breast, a cup of Greek yogurt, a can of tuna, two eggs, or a serving of lentils each deliver a solid chunk of protein, so two protein anchored meals plus one rich snack usually closes the gap. Powder is just convenience, not a requirement. Use the calculator above to get your daily target first, then see whether your regular meals already get you there before buying anything.
How do I know if I'm not getting enough protein right now?
Common signs are feeling hungry soon after eating, slower recovery from workouts, losing strength while dieting, and hair or nails that seem weaker than usual. None of these proves anything on their own, since sleep and calories play a role too. The honest check is to log what you eat for a few days and compare it with the daily target from the calculator above, most people are surprised by how low their actual intake is.
Do older adults need more protein than standard advice says?
Yes, muscle loss with age (sarcopenia) means adults over 50 generally benefit from more protein than the basic 0.8 grams per kilogram guideline, especially when they exercise. Higher intake supports strength, balance, and recovery from illness or injury. If you're in this group, choose the upper end of the activity band in the calculator above, and talk to your doctor if you have any health conditions.
Frequently asked questions
How many calories should I eat to lose weight?
Start from your maintenance (TDEE) and subtract about 500 a day. That is roughly 0.5 kg of fat loss per week. The calculator shows a gentle −250 and a standard −500 target. Pick the one you can sustain, because a moderate deficit you keep beats an aggressive one you abandon. Adjust after 2 to 3 weeks of real results.
What is the difference between BMR and TDEE?
BMR is what you burn at complete rest over 24 hours, heartbeat, breathing, brain. TDEE adds everything else on top, via the activity factor: walking, work, exercise. Plan your diet around TDEE, never BMR, since you do not spend whole days motionless. Think of BMR as the floor and TDEE as the budget.
How accurate is the Mifflin-St Jeor equation?
It is the most validated formula for the general population, usually within 10% of lab measured metabolic rate. Very muscular or very lean people may burn more than it predicts, since it does not account for body composition. Treat it as a well calibrated starting point, then adjust to what the scale actually does.
I am in a deficit but not losing weight. What is happening?
Almost always, the deficit is smaller than it looks. Untracked snacks, drinks, cooking oils and weekend meals quietly erase it, studies show people under report intake by 30 to 50%. Track everything honestly for a week, weigh food where you can, and keep sleep and stress in check: both drive the hunger hormones that sabotage deficits.
How many calories per day do I need for my age and activity level?
It varies a lot: a sedentary adult might maintain on around 1,800 to 2,200 kcal while a very active one needs 2,800 or more, and needs drift down with age as muscle mass declines. Enter your age, gender, height, weight and activity level above and the calculator estimates your personal maintenance figure, eat near it to hold weight, below it to lose, above it to gain.
Should I eat back my exercise calories?
Usually only some of them. Trackers and gym machines routinely overestimate burn, often by 20 to 40 percent, so eating back every calorie can quietly erase your deficit. A safer rule: eat back roughly half of what your tracker claims, watch the scale for two weeks, then adjust. If weight loss stalls, you were over crediting the exercise.
What are the activity multipliers in the calorie formula?
Your BMR is multiplied by an activity factor to get TDEE: 1.2 for sedentary (desk job, no exercise), 1.375 for lightly active (light exercise 1 to 3 days a week), 1.55 for moderately active (3 to 5 days), 1.725 for very active (hard exercise 6 to 7 days), and 1.9 for extra active (physical job plus training). Most people overestimate here, if you are unsure, pick one level lower than your gut says, then adjust after 3 weeks of scale data.
How many calories should I eat to gain muscle without much fat?
Aim for a small surplus, about 200 to 300 calories above your TDEE, paired with progressive strength training and roughly 1.6 to 2.2 g of protein per kg of body weight daily. That surplus is enough to build around 0.25 to 0.5 kg of muscle a month for a beginner; a bigger surplus mostly just adds fat faster without speeding up muscle growth.
What is the lowest safe number of daily calories?
As a general floor, health authorities advise against going below about 1,200 calories a day for women or 1,500 for men without medical supervision, below that, nutrient deficiencies, muscle loss and hormonal disruption become real risks. Note that this calculator's BMR is already near that floor for smaller people, which is why deficits should come off TDEE, not BMR.
What is a safe calorie deficit for weight loss?
Most guidelines recommend a 500-calorie daily deficit for about 0.5 kg per week of loss. Deficits larger than 750 to 1000 calories can cause muscle loss and nutrient deficiencies, consult a professional for aggressive targets.