Cycle and pregnancy dates, estimated honestly
Health calculators work with dates and cycles. They answer questions like when the next period is due, which days are the fertile window, and how far along a pregnancy might be. Every answer comes from the dates you enter and the average cycle lengths the maths assumes, so the tools are best used for planning and awareness, never as a diagnosis.
The period calculator forecasts your next six cycles from your last period and your usual cycle length. The ovulation calculator works backwards from the next expected period to estimate ovulation day and the fertile days around it, and the conception calculator estimates when conception likely happened from a due date or a last period. The pregnancy calculator turns a last period date, a conception date or an ultrasound date into an estimated due date and a week by week timeline.
Averages hide a lot. Cycles shift with stress, illness, travel and plenty of ordinary life, and two people with the same cycle length can ovulate days apart. If a forecast matters for a real decision, confirm it with a test or a clinician rather than a web page. These tools collect nothing: the dates you type stay in your browser, and there is no account and no history kept on our side.
There are only four health calculators here, deliberately. Each one does a single job carefully instead of bundling a dozen rough estimates into one page. Pick the question you actually have, enter the dates as exactly as you can, and read the result as a well informed estimate: useful for planning, honest about its limits.