Pregnancy · Fun
Chinese Gender Predictor Chart
Ancient Chinese gender prediction chart cross-referencing mother's lunar age + conception month. Fun cultural tradition with honest 50% accuracy (Villamor 2011, 2.8 million births). Use for amusement, not decisions.
Last reviewed 29 May 2026
Traditional Chinese gender chart
What does the Chinese chart say?
Enter the mother’s age (17–44) and the month she conceived (1–12) to see what the traditional Chinese chart predicts.
Is the Chinese Gender Chart accurate?
No — it’s folklore, not science. The definitive validation study (Villamor 2011) in 2.8 million Swedish births found accuracy of 50.2%— exactly chance. Smaller studies (Ostler 2010) similar finding. Despite folk claims of 90%+ accuracy, the chart has NO predictive value.
What is the Chinese Gender Chart?
Ancient Chinese gender prediction chart, allegedly discovered in a Qing-dynasty royal tomb ~700 years ago. Cross-references the mother’s LUNAR AGE at conception with the LUNAR MONTH of conception to predict boy or girl.
- Lunar age ≈ Western age + 1 (Chinese tradition counts gestation as year 1).
- Lunar month differs slightly from Western calendar (lunar new year typically late Jan / early Feb).
Widely used in Chinese culture; spread globally as “fun” prediction.
How does the chart work?
- Calculate lunar age at conception (usually Western age + 1).
- Calculate lunar month of conception.
- Cross-reference on chart — cell shows B (boy) or G (girl).
Calculator above does conversions automatically.
Why is the Chinese chart still popular?
Cognitive biases:
- Selection bias — accurate predictions remembered; wrong ones forgotten.
- Confirmation bias — after birth, parents recall the prediction as if it “knew”.
- 50% base rate — half of all predictions are right by chance.
- Cultural tradition — centuries old; emotional weight.
- Harmless fun — no obvious downside.
What are accurate gender prediction methods?
- NIPT (blood test): from 10 weeks. 99%+ accurate.
- Early gender scan: 13-16 weeks. 75-95%.
- 20-week anomaly scan: 95-99% with experienced sonographer.
- Amniocentesis / CVS: 100% but invasive; only for medical reasons.
How does NIPT actually determine sex?
Analyses CELL-FREE FETAL DNA in maternal blood (fetal DNA crosses placenta into mum’s bloodstream from 10 weeks). Looks for Y-CHROMOSOME material:
- Y-chromosome present → boy
- Y-chromosome absent → girl
99%+ accurate from 10 weeks. Originally developed for chromosomal screening (Down, Edwards, Patau) — sex revelation a by-product.
When does baby's sex actually develop?
- At fertilisation: sex set by sperm chromosome (X = girl, Y = boy).
- 6-7 weeks gestation: gonads decide testis vs ovary (SRY gene triggers male path).
- 9-12 weeks: external genitalia visibly different.
- From 14 weeks: ultrasound can sometimes ID.
- 20 weeks: usually clearly visible on anatomy scan.
Different scenarios — what to make of the chart
Scenario 1: Chart says 'girl', NIPT says 'boy'
Believe NIPT. 99%+ accuracy vs chart 50%. Chart was wrong as expected.
Scenario 2: Chart says 'boy', strong gut feeling 'girl'
Both ~50% accurate. Wait for medical confirmation (NIPT, 20-week scan). Don’t make decisions on either.
Scenario 3: Multiple online charts give different results
Common — different versions and lunar conversion errors. None more accurate than others. All 50%.
Scenario 4: Already know baby's sex from NIPT — chart 'matches'
50% of the time it will match by chance. Doesn’t validate the chart.
Scenario 5: Doing chart at baby shower for fun
Perfect use case. Fun, low stakes, cultural connection. Just don’t spend money on gender-specific items based on it.
Common myths debunked
- “Chinese chart 90% accurate” — no. Villamor 2011: 50.2%.
- “Updated / authentic version is better” — no. Structure means all versions ~50%.
- “Used by Chinese royalty for centuries” — cultural artefact, not predictive.
- “If you do it three times and average, more accurate” — no. Averaging chance still equals chance.
- “Works for IVF babies” — no different. Still 50%.
Sources
- Villamor E, et al. Accuracy of the “Chinese gender chart”. Pediatr Perinat Epidemiol 2011.
- Ostler S, et al. Validation studies of folk gender prediction. J Reprod Med 2010.
- Allyse M, et al. Non-invasive prenatal testing: a review. Int J Womens Health 2015.
- McKenna DS, et al. Gender differences in fetal heart rate. Fertil Steril 2006.
- NHS. Boy or girl — finding out.
Recommended for this calculator
Frequently asked questions
Is the Chinese Gender Chart accurate?
NO — it's folklore, not science. Peer-reviewed validation in 2.8 MILLION SWEDISH BIRTHS (Villamor 2011) found accuracy of 50.2% — exactly chance. Smaller studies (Ostler 2010 J Reprod Med) similar finding ~50%. The chart uses MATERNAL AGE + CONCEPTION MONTH to predict sex; both unrelated to chromosome-determined sex. Despite folk claims of 90%+ accuracy and centuries of tradition, the chart has NO predictive value. Fun cultural artefact.
What is the Chinese Gender Chart?
Ancient Chinese gender prediction chart, allegedly discovered in a Qing-dynasty royal tomb ~700 years ago (though origins disputed). Cross-references the mother's LUNAR AGE at conception with the LUNAR MONTH of conception to predict boy or girl. Lunar age ≈ Western age + 1 (Chinese tradition counts gestation as year 1). Lunar month differs slightly from Western calendar (lunar new year typically late Jan / early Feb). Widely used in Chinese culture; spread globally as 'fun' prediction.
How is the Chinese gender prediction calculated?
Three steps: (1) LUNAR AGE at conception — usually Western age + 1, sometimes +2 if conceived before lunar new year. (2) LUNAR MONTH at conception — the calendar month of fertilisation, adjusted for lunar calendar. (3) Cross-reference on the chart. Calculator does conversions automatically. Read the chart cell where age meets month — letter B (boy) or G (girl). That's it. Despite its complexity, accuracy is still 50%.
Why is the Chinese chart still popular if it's 50% accurate?
Cognitive biases: (1) SELECTION BIAS — accurate predictions are remembered and shared; wrong ones forgotten. (2) CONFIRMATION BIAS — after birth, parents recall the chart's prediction as if it 'knew'. (3) 50% BASE RATE — half of all predictions are right by chance alone. (4) CULTURAL TRADITION — passed down for centuries, builds emotional weight. (5) HARMLESS FUN — no obvious downside to trying. Most who use it know it's not scientific but enjoy the tradition.
Are there any actually-accurate gender prediction methods?
Yes — modern medical ones. NIPT (Non-Invasive Prenatal Test) blood test from 10 weeks: 99%+ accurate. ULTRASOUND from 14-16 weeks: 75-95%; 20-week anomaly scan: 95-99%. AMNIOCENTESIS / CVS: 100% but invasive (only for medical reasons). Folk methods (Chinese, Mayan, wives' tales, heart rate, bump shape): ~50% accuracy = chance.
How does NIPT determine baby's sex?
Non-Invasive Prenatal Test analyses CELL-FREE FETAL DNA in maternal blood (fetal DNA crosses placenta into mum's bloodstream from 10 weeks). Looks for Y-CHROMOSOME material: present = boy, absent = girl. 99%+ accurate from 10 weeks of pregnancy. Originally developed for chromosomal screening (Down syndrome, Edwards, Patau syndromes) — sex revelation is a by-product. Available privately in UK (~£200-500); sometimes covered by US insurance for high-risk pregnancies.
When does my baby's sex actually develop?
Sex is determined at FERTILISATION — sperm carrying X chromosome = girl; Y chromosome = boy. ANATOMICAL DIFFERENTIATION starts at 6-7 weeks gestation as the gonads decide testis vs ovary (SRY gene on Y chromosome triggers male path). EXTERNAL GENITALIA become visibly different from 9-12 weeks. The genital tubercle is identical in both sexes until ~9 weeks; ultrasound can sometimes ID from 14 weeks; reliably from 20 weeks.
Is the Chinese chart based on real medicine?
No. The chart predates modern biology by centuries. Ancient Chinese medical theories used yin/yang, five elements, lunar timing — pattern-based not evidence-based. The chart almost certainly emerged as ROYAL FAMILY ASTROLOGY rather than genuine medical observation. Modern genetics (DNA, chromosomes, SRY gene) is what actually determines sex. The chart is a beautiful cultural artefact that doesn't predict anything.
Why does the chart use lunar age and month?
Cultural calendar tradition. Chinese counts age from CONCEPTION (year 1 at birth) and uses LUNAR CALENDAR (12 lunar months tied to moon phases, with a leap month every few years). Western calendar uses solar year + Gregorian months. Conversion needed for the chart to 'work'. Most online Chinese gender calculators do the conversion automatically. The use of lunar reckoning gives it ancient mystique but doesn't add predictive accuracy.
Can the Chinese chart predict twin sexes?
No more than for singletons. The chart gives one answer (B or G) per mother + month combination — it can't predict mixed-sex twins. Twins are common (~1-3% of pregnancies; higher with IVF). About 1/3 of twins are mixed-sex. The chart fundamentally can't distinguish. NIPT can detect Y chromosome material in twin pregnancies but can't tell you which twin is which sex (helpful only if same-sex result). Ultrasound at 20 weeks gives both twins separately.
If I take the chart from different sources I get different answers
Common problem. Different versions of the 'authentic' chart circulate online, sometimes with slightly different cells. Lunar calendar conversion errors compound the variability. Some apps round age or month differently. None of this matters — all versions are equally accurate (50%). If you really want a prediction, use medical methods.
Why is the Chinese chart endorsed by some 'studies'?
Selectively-reported small-cohort 'studies' have claimed 70-90% accuracy. These are usually: (1) self-selected samples (only people who 'used the chart and remembered' participated); (2) tiny sample size; (3) confirmation-biased recall. The DEFINITIVE Swedish 2.8-million birth registry study (Villamor 2011) put accuracy at 50.2% — that's the rigorous answer. Don't believe Instagram '95% accurate' claims.
What about the new 'updated' or 'authentic' charts?
Some versions claim to be 'authenticated by tomb discovery' or 'verified by elder Chinese astrologers'. None of this changes the underlying statistics. The chart's structure assigns roughly half boys and half girls to each maternal-age-month combination — so any version will achieve ~50% accuracy. 'Updated' is marketing.
Should I make decisions based on the Chinese chart?
No big decisions — paint nursery, buy gender-specific items, finalise name choices. Fine for: amusement, conversation starter at baby shower, fun activity with partner / family. Don't bet money on it (one website does 'gender betting' — house wins). Use NIPT or ultrasound for actual planning.
Is there a 'best' folk method?
All folk methods (Chinese, Mayan, ring swing, wives' tales) are ~50% accurate — chance. No 'best'. PERSONAL ENJOYMENT depends on cultural connection (Chinese heritage families may enjoy the Chinese chart more; Mayan-heritage families the Mayan). Modern medicine (NIPT, ultrasound) is the only 'best' for accuracy.
How does this relate to other calculators on BumpBites?
Companion: /calculators/gender-predictor for Mayan + method comparison; /calculators/wives-tales-gender for compiled wives' tales; /calculators/eye-colour-predictor for baby's eye colour; /calculators/baby-personality-quiz for trait fun; /calculators/due-date for actual pregnancy dating; /calculators/baby-names.