Resources
All pregnancy calculators
Every tool on babybumpkit — free, mobile-friendly, and based on standard medical formulas. New calculators are added regularly.
Available calculators
Free pregnancy due date calculator using your last period and cycle length. Naegele's rule, the same formula your doctor uses.
Estimate your due date from conception or IVF transfer — for when you've tracked ovulation precisely (266 days).
Estimate your implantation window and the earliest day a pregnancy test could turn positive.
Try the Chinese gender calendar, Mayan method, and parent-traits predictor side by side. Just for fun.
About these calculators
Every calculator on babybumpkit is built around a single rule: get the math right and cite the source. The formulas come from major medical bodies — ACOG, the Mayo Clinic, the NHS, NIH MedlinePlus — and each tool page links the specific paper or guideline it relies on. We never claim “100% accurate” results; we say estimates, because that is what the math actually gives you.
All calculations run in your browser. Your inputs are never sent to our servers. There are no accounts, no email captures, and no tracking cookies.