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.
Predict your fertile window, peak fertility days, and next period from your last menstrual period and cycle length.
Predict expected hCG levels or compare two test results to calculate doubling time in early pregnancy.
Estimate your due date from conception or IVF transfer — for when you've tracked ovulation precisely (266 days).
Work backward from your due date or last period to estimate when you conceived.
Estimate your implantation window and the earliest day a pregnancy test could turn positive.
Find the earliest date each kind of test (blood, sensitive home, standard home) will give a reliable result.
Find your BMI-based recommended pregnancy weight-gain range using the IOM 2009 guidelines. Track progress by week.
Try the Chinese gender calendar, Mayan method, and parent-traits predictor side by side. Just for fun.
The traditional Chinese gender chart with a calculator and the full 28×12 lookup table.
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.