About ExpectCalc

ExpectCalc is a small, independent website of pregnancy date calculators, built and maintained by Nan Liang, an independent developer. It exists because the dominant pregnancy calculators online all run the same hidden math — a last period plus 280 days, with a 28-day cycle assumed whether or not you have one — and then return a single overconfident date.

The approach here is different. Every calculator accepts every anchor you can honestly provide — last period, your actual cycle length, ovulation test dates, conception, early ultrasound, IVF transfer date — computes each independently, and shows you where they agree and where they disagree. When the anchors spread, the site says so, because a visible disagreement is more useful than a hidden one.

The site is free, requires no account, runs no server-side processing of your health inputs (all calculation happens in your browser), and carries no advertising networks at launch. It makes no money from your answers and has no app to funnel you into.

How content is reviewed

Every medical claim on this site is tied to a primary source — ACOG committee opinions, Institute of Medicine reports, or the original peer-reviewed studies — listed at the bottom of each page. Calculators encode published clinical conventions (the 266-day biological length, IOM weight-gain ranges, hCG interpretation bands) rather than original research, and each page states its sources and its known limitations.

Content is written and maintained by the developer and reviewed against current guidance before publication. Our editorial and medical review policy describes the process, including how errors are corrected: email corrections to support@expectcalc.com and they are triaged and, when valid, fixed and re-reviewed.

More about the developer: Nan Liang, independent developer. Nan Liang also writes at javaeye.dev, with a profile and other projects there.