Mayan Calendar Gender Calculator

What the Mayan Gender Predictor Actually Is

Despite the name, there's no documented Maya source for this method — no codex, no inscription, nothing an archaeologist has traced back to actual Maya calendar-keeping. It's a modern chart that spread through pregnancy forums under an ancient-sounding name, in the same family as other gender-prediction folklore like the Chinese gender chart. We're building it because people search for it and enjoy it, not because it works: statistically it lands right about as often as a coin flip, since a baby's sex is determined by chromosomes at conception and has no known link to the mother's age or the conception month.

How to Use This Calculator

Enter the mother's age at the time of conception (not at delivery) and the month conception occurred. If you're not certain of the exact conception date, counting back roughly two weeks from a missed period is the usual estimate people use for this kind of chart.

How We Calculate It

The rule is a simple parity match: if the mother's age at conception and the number of the conception month (January = 1 through December = 12) are both even or both odd, the chart predicts a girl. If one is even and the other is odd, it predicts a boy. A 29-year-old conceiving in March — 29 and 3, both odd — gets a girl prediction; the same mother conceiving in April — 29 and 4, mismatched — gets a boy prediction instead.

A Few Notes

Treat this strictly as entertainment for a baby shower or a fun guessing game with family, not as information to plan around. If you want an actual read on your baby's sex, that comes from an anatomy ultrasound (typically 18–20 weeks) or a blood-based prenatal test recommended by your provider — nothing about a calendar or a mother's age changes what an ultrasound or a genetic test will show.