How the Mayan Gender Chart Works
The whole “chart” is one rule. Take the mother’s age at conception and the number of the conception month (January = 1, December = 12). If the two numbers are both even or both odd — girl. If one is even and one is odd — boy. A 28-year-old conceiving in June (28 even, 6 even) gets “girl”; the same mother a month later (28 even, 7 odd) gets “boy”. You can see why forums love it — it takes ten seconds and feels pleasingly mathematical.
A note on versions: a minority of calculators online apply the rule to the conception year instead of the month. The widely shared version — the one used by every major source we checked — uses the month, so that’s what our calculator does. Since neither variant can beat a coin flip, the choice costs nothing but consistency.
Honest Part One: It’s Probably Not Mayan
The ancient Maya were extraordinary astronomers with some of the most sophisticated calendar systems ever devised — the Long Count, the 260-day Tzolk’in, the 365-day Haab’. What no historian or archaeologist has documented is a Maya even/odd gender-prediction rule. The “Mayan gender predictor” appears to be a modern internet creation wearing an ancient name — it spread through pregnancy forums, not through any codex. We’ll happily show you the game; we won’t pretend it’s archaeology.
Honest Part Two: Accuracy Is a Coin Flip
Whether your age is even or odd has no biological pathway to which sperm reaches the egg — so the method’s accuracy is ~50%, exactly what guessing gets you. Nobody has bothered running a large formal study on this one (its cousin, the Chinese calendar, was tested against 2.8 million births and landed precisely on chance), and the arithmetic here is even simpler: a parity rule splits all mothers into two halves, and roughly half of babies in each half are boys. If you want a real answer, NIPT from 10 weeks or the 18–22 week anatomy scan — see every method by week.
That said, there’s a genuinely fun way to use it: get the prediction now, write it down, and check it against your NIPT result or anatomy scan later. Half of the parents in any forum thread will report it “worked” — which is exactly what a coin flip guarantees, and watching that play out in the comments is half the entertainment. The same 50% applies to every other tradition in the genre — we ran the top ten gender old wives’ tales against the research, heart-rate rule included.
Mayan vs Chinese Gender Predictor
The two calendar legends get mentioned in the same breath, but they work differently:
| Aspect | Mayan | Chinese |
|---|---|---|
| Inputs | Age + month (ordinary numbers) | Lunar age + lunar month |
| Mechanism | One even/odd parity rule | 28×12 lookup chart |
| Claimed origin | “Ancient Maya” (undocumented) | “Qing-dynasty tomb” (undocumented) |
| Accuracy | ~50% | ~50% (tested on 2.8M births) |
Want the other calendar legend’s opinion too? Try the Chinese gender predictor with the full 2026 calendar table — it’s the more elaborate of the two games. And when you’re ready for evidence instead of parity, our free AI gender predictor reads your actual ultrasound.
Frequently Asked Questions
How does the Mayan gender predictor work?
It compares two numbers: the mother’s age at conception and the number of the conception month (January = 1 … December = 12). If both are even or both are odd, the prediction is a girl; if one is even and one is odd, a boy. That’s the whole method.
How accurate is the Mayan gender predictor?
About 50% — the same as flipping a coin. Parity of two numbers has no biological connection to your baby’s chromosomes, so it can’t do better than chance. Any site claiming higher accuracy for it is marketing.
Did the ancient Maya really use this method?
There’s no historical evidence they did. The Maya had sophisticated calendars, but no documented gender-prediction chart like this — the “Mayan gender predictor” is a modern internet creation with an ancient-sounding name attached.
What’s the difference between the Mayan and Chinese gender predictors?
The Chinese calendar uses a 28×12 lookup chart with lunar age and lunar month; the Mayan method is a single even/odd rule on ordinary age and month. Different mechanics, identical accuracy: both land at ~50%, because neither looks at the baby.
The legend guessed. Now ask your ultrasound.
Our free AI predictor looks at the real evidence in your scan — nub angle, visible anatomy — gives a confidence score, and says “unclear” honestly when there’s nothing to read.
Try the Free AI Gender Predictor