Chinese Gender Calendar & Predictor
The chart is indexed by lunar age and lunar conception month. Most calculators quietly feed it your Gregorian month and call it a day. This one does the real conversion, shows you the working — and is straight with you about the odds.
When Can You Actually Find Out the Sex?
If you came here for fun, enjoy the chart. If you came here because you genuinely want to know, here is the timeline that actually applies — and the good news is that it starts earlier than most people expect.
NIPT blood test
A maternal blood draw that looks for Y-chromosome DNA. Over 99% accurate for sex, and it is the earliest reliable answer available.
Nub theory (at a scan)
Sonographers can sometimes guess from the genital tubercle angle. It is a guess, not a report line, and it is wrong often enough that nobody should paint a nursery on it.
CVS
Diagnostic, essentially definitive, but invasive and offered for genetic reasons — not to satisfy curiosity.
Amniocentesis
Also diagnostic and definitive, also offered for medical indications rather than sex alone.
Anatomy scan
The standard answer for most pregnancies. Highly accurate when baby cooperates — and occasionally the cord or a well-placed hand means you leave still not knowing.
Not sure how many weeks along you are? Our due date calculator gives your gestational age to the day from your last period, a conception date, an IVF transfer or a dating scan.
How the Chinese Gender Calendar Works
The chart is a grid: lunar ages 18–45 down the side, lunar months 1–12 across the top, Boy or Girl in every cell. Simple to read — and easy to read wrong, because both inputs are lunar and neither matches the calendar on your wall.
Lunar age (虚岁)
You are 1 on the day you are born, and everyone gains a year together at Chinese New Year rather than on their birthday. So lunar age usually sits 1–2 years above western age, and a December baby and a January baby can share one.
Lunar month
Lunar months start at a new moon and run 29 or 30 days, so they drift against Gregorian months. Conceive in early February and you are usually still in the twelfth lunar month of the previous year — not the second.
That second box is the whole reason results differ between sites. A calculator that reads your Gregorian month straight off the date will put an early-February conception in column 2 instead of column 12, and hand you a different baby.
How Accurate Is It, Really?
It is a coin toss. That is not a figure of speech — it is the finding of the only large test ever run on the chart.
Researchers at the University of Michigan School of Public Health checked the method against 2,840,755 singleton births recorded in Sweden between 1973 and 2006. The agreement statistic came out at kappa = 0.0002, with a confidence interval straddling zero. Zero is what you would get from guessing. Accuracy did not improve for any group they tested — not by maternal age, education, BMI or number of previous births.
Why it still feels uncanny: with two possible answers, the chart is right for half of everyone who tries it. Those people tell the story. The other half quietly forget they ever checked. That asymmetry — not the chart — is what keeps the 90%-accuracy claims alive.
Anyone quoting a specific accuracy figure above 50% is quoting something that has never been measured.
Where the Chart Actually Comes From
Almost every page repeats the same origin story: a 700-year-old chart, discovered in a royal tomb, kept by the Qing imperial family, now held at the Beijing Institute of Science. It is a great story. It also does not hold together.
- The dates contradict each other. The Qing dynasty ran from 1644 to 1911 — under 400 years ago. A 700-year-old chart would predate it by roughly three centuries. Both claims get repeated in the same paragraph constantly, including, until recently, on this page.
- No verified original exists. There is no archaeological citation for the tomb, and no catalogued artefact anyone can point to.
- The format looks modern. A tidy grid of exactly ages 18–45 by months 1–12 reads like a printed table, not a manuscript.
None of which makes it worthless. Chinese numerology and lunar reckoning are genuinely old and genuinely rich, and this chart sits somewhere in that tradition. It just is not the authenticated imperial relic the internet keeps describing — and you deserve to hear that from the site handing you the prediction.
A practical consequence: the grids circulating online are not identical to each other. Decades of copying have introduced drift, which is the second reason two sites can disagree about your baby.
Old Wives' Tales, Scored Honestly
The Chinese chart has plenty of company. Here is how the popular ones hold up — including the one that turns out to have something behind it.
“Heart rate above 140 bpm means a girl”
No. Fetal heart rate tracks gestational age, not sex — it climbs to around 170 bpm by week 9 or 10 and settles after. Studies comparing first-trimester rates in male and female fetuses find no usable difference.
“Carrying high means girl, low means boy”
No. Bump shape comes from your abdominal muscles, torso length, the baby's position and how many pregnancies you have had.
“Sweet cravings mean girl, salty means boy”
No. Cravings have been studied repeatedly and do not sort by fetal sex.
“Bad morning sickness means a girl”
This one is the interesting exception. Severe hyperemesis gravidarum — the hospitalising kind, not ordinary nausea — has been associated with a modestly higher chance of a female fetus in large registry studies. It is a population-level tilt, not a prediction for you.
“The ring on a string test”
No. That is the ideomotor effect: tiny unconscious hand movements from the person holding the string.
The Mayan method is the other calendar people try: if the mother's age at conception and the conception month are both even or both odd it says girl, otherwise boy. No lunar conversion, no history to speak of, same 50% ceiling. If predictions are your thing, our baby blood type predictor is at least built on actual genetics.
Chinese Gender Predictor FAQ
How this calculator works, and what it isn't
Your two dates are converted to the Chinese lunisolar calendar using a standard 1900–2100 conversion table, validated against published Chinese New Year dates and leap months. Lunar age is counted the traditional way — 1 at birth, incrementing at Chinese New Year. The chart is then read at that lunar age and lunar month. The grid you see on screen is the same data that produced your answer, so the highlighted cell can never disagree with the headline.
Everything runs in your browser. Nothing you enter is transmitted or stored.
This is a folk tradition presented for entertainment. It has no predictive validity, it is not a medical tool, and it should never inform a decision about a pregnancy. For an answer you can rely on, speak to your provider about NIPT or the anatomy scan.
Reviewed 26 August 2026. Educational information only — not medical advice.
Sources
- Villamor E, Dekker L, Svensson T, Cnattingius S. Accuracy of the Chinese lunar calendar method to predict a baby's sex: a population-based study Paediatric and Perinatal Epidemiology 2010;24(4):398–400.
- NHS. Screening tests in pregnancy
- American College of Obstetricians and Gynecologists. Prenatal Genetic Screening Tests
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