Chinese Gender Predictor
Every baby shower has the same party game: everyone guesses boy or girl, and somebody always drags out the ancient Chinese gender chart. Legend says it was buried in a royal tomb near Beijing over 700 years ago, and that it reads a baby's sex from just two inputs, the mother's lunar age and the lunar month of conception. This predictor does the look up for you: enter the mother's date of birth and the conception date, and it applies the traditional simplified conversions, finds the matching cell, and delivers the chart's centuries old verdict. Now the part that matters more than the result: the chart has no scientific basis. A landmark study of 2.8 million Swedish births found it right about half the time, exactly the hit rate of a coin toss. Chromosomes decide a baby's sex at conception, not calendars. So enjoy it the way it was meant to be enjoyed: a cultural curiosity, a shower game, a little old world theatre. For real answers, the 18 to 22 week ultrasound, or NIPT from week 10, is what actually delivers. Based on the traditional Qing dynasty chart using lunar age and lunar conception month, just for fun, not a medical prediction.
Last updated: October 22, 2026
Your result
Just for fun: this chart is a centuries old tradition with no scientific basis.
The formula
Lunar age = conception year − birth year + 1 (traditional simplified rule)Lunar conception month ≈ Gregorian conception month (simplified; true lunar conversion is more complex)Prediction = chart cell at lunar age row × lunar month column (B = boy, G = girl)The traditional chart only covers lunar ages 18 to 45
A worked example
A mother born 14 March 1998 with conception on 10 June 2026: lunar age = 2026 − 1998 + 1 = 29, lunar month = 6. Row 29, column 6 of the traditional chart reads B, the chart predicts a boy. Remember: it is a folk tradition, not science.
More about the Chinese Gender Predictor
How to read the chart in 30 seconds
The chart is a single grid: the mother's lunar age runs down the side (18 to 45), the lunar month of conception runs across the top (1 to 12), and every cell holds a B for boy or a G for girl. Find your row, find your column, read the letter. That is the entire method.
This predictor handles both conversions for you. Enter the mother's date of birth and the conception date, and it works out the lunar age, picks the lunar month, and returns the chart's verdict in an instant, no squinting at a printed grid needed.
What "lunar age" really means (and our honest shortcut)
In the traditional reckoning you turn 1 at birth, and everybody ages a year on Lunar New Year, so lunar age is usually your Gregorian age plus one, occasionally plus two if your birthday falls late in the lunar year. A truly precise conversion needs the exact Chinese New Year dates for both years.
This calculator uses the simplified rule most online predictors use: lunar age = conception year − birth year + 1. It is an approximation of the tradition rather than the full lunisolar maths, but since the chart itself is folklore, the shortcut suits the spirit of the thing.
The 700-year-old legend
The story goes that the chart turned up in a royal tomb near Beijing some 700 years ago, and that the original now rests in the Institute of Science in Peking. It is a wonderful story — though it is worth knowing that published versions of the grid differ slightly from source to source, which is precisely what you would expect of a legend rather than a document.
This predictor uses the most widely published version of the grid, the Qing palace chart as printed by the major reference sites. Count the legend as part of the fun: cultural theatre, not a medical text.
So… how accurate is it? The honest answer
About as accurate as a coin flip. A large epidemiological study ran the chart's algorithm against 2,840,755 Swedish births across 33 years and found it right 50.4% of the time, essentially identical to the natural birth ratio of about 105 boys to 100 girls. In other words, the chart performs exactly as well as chance.
That does not make it worthless; it makes it a game. Enjoy the reveal, drop it in the family group chat, let the grandparents argue it out. Just do not plan a nursery around it, and never make a medical decision from it.
Planning or predicting? Using the chart both ways
Already pregnant? Enter the conception date, or your estimated ovulation date if the exact day is fuzzy, and the chart gives its verdict for this pregnancy. Trying to conceive? Enter a future month and scan ahead instead: the chart will cheerfully tell you which coming months it links to a boy or a girl at your lunar age.
Either way, the biology does not negotiate: no month genuinely favours a boy. The planner view is entertainment, a way to daydream with a calendar, not a fertility strategy.
What actually decides boy or girl
A baby's sex is fixed at conception by the father's sperm, an X chromosome makes a girl, a Y makes a boy. No month, maternal age or calendar shifts those odds, which sit near 50/50 for every pregnancy.
For a real answer, the reliable routes are NIPT (a blood test, over 99% accurate from week 10), the mid pregnancy anatomy ultrasound (about 98 to 99% accurate at 18 to 22 weeks), and diagnostic tests like CVS or amniocentesis. The chart is the warm up act; these are the headliners.
Why your lunar age can sit two years above your real age
Take a mother born on 30 December 2000 who conceives on 10 January 2026. By Western counting she has just turned 25, her birthday was eleven days before conception. The chart wants her lunar age instead, and the traditional rule used here is conception year minus birth year plus one: 2026 − 2000 + 1 = 27. She is, for chart purposes, two years older than the age on her birthday cake, and that is not a mistake in your inputs.
Two separate conventions stack up to create the gap. Traditional counting treats a baby as already one year old at birth, which supplies the plus one. Age then traditionally rises for everyone at the New Year rather than on individual birthdays, so someone born in the last days of December is counted as turning two almost immediately. Enter the row for 27 even though 25 feels right, using your Western age is the single most common reason two people get different predictions from the same chart.
Three input slips that flip the prediction
The first slip is entering the month you are due, or the month you found out, instead of the month of conception, conception typically sits about two weeks after the last period, and a one month shift moves you to a different column entirely. The second is using your age today when the pregnancy began months ago, especially if a birthday fell in between. The third is forgetting that the chart’s months are lunar: near a month boundary, the lunar month can lag the calendar month you remember, nudging borderline cases into the neighbouring column.
None of these slips matter medically, and that is the right frame for the whole exercise. The chart is a folk tradition to enjoy at a baby shower; ultrasound scans and prenatal blood tests are the tools that actually observe the baby. If a prediction from this page and a scan ever disagree, believe the scan, and if two websites disagree with each other, the difference is almost always one of the three input slips above, or a slightly different traditional chart.
How to use the Chinese Gender Predictor
- Enter the mother's date of birth.
- Enter the conception date, or a future month if you are planning ahead.
- Hit Calculate to see the lunar age, lunar month and the chart's verdict.
- Enjoy the result as a bit of fun. It has no scientific basis and is no substitute for medical testing.
Frequently asked questions
How does the Chinese gender predictor work?
It consults a traditional grid, the mother's lunar age down one side, the lunar month of conception across the top, where every cell reads B (boy) or G (girl). Enter the two dates and the calculator does the lunar conversions and the look up for you.
How do I calculate my lunar age for the chart?
The simplified rule: lunar age = conception year − birth year + 1. A mother born in 1998 conceiving in 2026 lands on a lunar age of 29. The full traditional reckoning, aged 1 at birth, +1 at Lunar New Year, is more intricate; this calculator sticks with the simplified version most online predictors use.
Which conception date should I enter if I am not sure?
Use your estimated ovulation date, roughly 14 days after the first day of your last period in a 28 day cycle. The chart only cares about the month, so being a few days out rarely changes the answer.
What if my lunar age is under 18 or over 45?
The traditional chart only covers lunar ages 18 to 45, so outside that range there is simply no row to look up, the calculator cannot give a verdict. That is a limit of the folklore, not of the tool.
Does the chart work for twins?
The legend never covered twins, one cell, one letter. If you are expecting multiples, take the chart's single verdict as the game it is, and wait for the ultrasound: the only fun reveal that is also real.
What are the real medical ways to find out the baby's sex?
NIPT, a maternal blood test, is over 99% accurate from week 10. The mid pregnancy anatomy ultrasound runs about 98 to 99% accurate at 18 to 22 weeks. CVS and amniocentesis are definitive, but they carry a small miscarriage risk and are only done for medical reasons.
Does the chart work for IVF pregnancies?
You can still enter the conception date for an IVF pregnancy and get a result, since the chart only needs a date and the mother's lunar age. But the same honesty applies: the prediction is for fun, not science. A baby's sex is decided by chromosomes at conception, so an IVF baby is no more predictable by the calendar than any other.
How accurate is the Chinese gender chart?
Not scientifically accurate, studies put it at roughly 50 to 55%, barely better than chance. It is a 700-year-old tradition based on the mother's lunar age and lunar conception month, and health authorities don't endorse it. Use it for fun; an ultrasound around week 18 to 20 gives the real answer.
Does it matter if conception fell just before or after Lunar New Year?
In the strictest traditional counting it can, because lunar age was reckoned to increase for everyone at the New Year rather than on birthdays, and lunar months follow the moon rather than the calendar. This predictor uses the simplified rule, conception year minus birth year plus one, with the calendar month standing in for the lunar month, so a conception near the boundary may sit one row or column off from a fully converted traditional reading. Treat borderline results as especially playful.
Can I use the chart before conceiving to aim for a boy or a girl?
People traditionally used it both ways, and nothing stops you reading it forwards: pick your lunar age row for the coming year and note which conception months the chart marks B or G. Just hold the plan lightly. The chart has no mechanism to influence biology, the baby’s sex is set at conception by the sperm, so treat month picking as a bit of fun layered over your real family timing, never as a reason to delay or rush a pregnancy.