The Chinese gender chart

The full table, how to read it, and what happened when someone checked it against 2.8 million real births.

Updated September 2026 · Grandma's Guess

The Chinese gender chart is the most searched-for pregnancy prediction method in the world. It asks two things — how old you were when you conceived, and which month it happened — and returns a confident answer. The full chart is below, along with the two things most pages leave out: where it actually came from, and what happened when researchers tested it against millions of real births.

The chart

Find your lunar age down the left, the month of conception across the top. B is boy, G is girl.

Lunar ageJanFebMarAprMayJunJulAugSepOctNovDec
18GBGBBBBBBBBB
19BGBGBBBBBBGG
20GBGBBBBBBBBG
21BGGGGGGGGGGG
22GBBGBGGBGGGG
23BBBGBBGBBGBB
24BGGBGBBGGGGG
25GBGBGBBGBBBB
26BGBGBBGBGBBG
27GBGBBGBBGGGB
28BGBBGBBGGGBB
29GBBGGBGGGBBB
30BBBBBBBBBGBB
31BGBBBGBBGBGB
32BBBBGBBGBBGB
33GBGBBBGBGBBG
34BGBBBGBGBGGB
35BBGBGBGBGBGB
36BGBBBBBBBBBG
37GBGBGBGBGBBB
38BGBGBGBGBBGG
39GBBBBBGBGBBB
40BGBGBGBGBGBB
41GBGBGBGBGGBG
42BGBGBGBGGBGB
43GBGBGBGGBGBB
44BBGGGBGBBGGB
45GGBGBGBGBBGB

Working out your lunar age

Lunar age is not your ordinary age. In the traditional Chinese reckoning you are one year old on the day you are born, and everyone gains a year at Lunar New Year rather than on their birthday. The rough version: add one to your ordinary age, and add two if your birthday falls after Lunar New Year but has not arrived yet.

The month should be the month of conception, not the month you found out — roughly two weeks after the start of your last period.

Where it came from

The story attached to almost every version online is that the chart was discovered in a royal tomb near Beijing, kept as an imperial secret because emperors badly wanted sons. It is a good story. It is also unverified — the tomb, the date and the discovery vary from telling to telling, and no source traces back to a documented artefact.

More usefully, historians and scholars of Chinese medicine point out that the chart does not appear to come from traditional Chinese medicine at all. TCM has an enormous documented literature on pregnancy, including pulse diagnosis and the balance of yin and yang, and the chart is not part of it. Whatever its origin, it sits outside the tradition it is usually credited to.

What happens when you test it

This is the part that settles it. Any method with two possible answers is right about half the time by accident, so the only question that matters is whether the chart beats a coin.

The largest test applied the chart's predictions to 2.8 million births in Sweden recorded between 1973 onward. The chart was correct roughly half the time — no better than chance. A dataset that size effectively closes the question.

A smaller 2023 study in Actual Gynecology took a different approach, running the chart against singleton pregnancies and measuring agreement statistically. It reported a kappa value of 0.002 with a p-value of 0.797 — kappa being a measure where 0 means no agreement beyond chance and 1 means perfect agreement. The authors concluded there was no agreement at all between predicted and actual sex.

The honest verdict

The chart is right about half the time, which is exactly what a coin manages. That does not make it worthless — it makes it a game, and games are allowed to be fun. It only becomes a problem if somebody paints a nursery on the strength of it.

Why it feels more accurate than it is

Two things. First, you only get one pregnancy at a time, so a single correct guess feels like evidence rather than a coin landing heads. Second, and more powerfully: the people who tell you the chart worked are self-selected. Everyone remembers the time it was right. Almost nobody brings up the time it was wrong, because there is no story in that.

This is the same reason grandmothers have such a strong reputation for knowing. They are right about half the time, and only half of that gets retold.

How to actually find out

An NIPT blood test can determine sex from about 10 weeks. The anatomy scan, usually between 18 and 22 weeks, is the more common route. Both are enormously more reliable than anything on this page.

Try the chart plus 107 other tales →

For entertainment only. Nothing here can tell you the sex of your baby, and none of it is medical advice. An ultrasound or NIPT blood test is how that question actually gets answered — ask your midwife or doctor.