About DueDateCalc

DueDateCalc is a small, single-purpose tool: it estimates pregnancy due dates the three standard ways — from a last period using Naegele's rule with a cycle-length adjustment, from a conception date using the 266-day count, and from an ultrasound's measured gestational age — and it shows the timeline that follows from the estimate.

It exists because most due date pages bury the calculator under ads, demand an email address, or present a single method as if it were a fact. A due date is an estimate with known assumptions, so this site shows its methods openly: every formula is explained in plain language on How Due Dates Are Calculated, and every tool page carries the same disclaimer — only around 5% of babies arrive on the estimated day, ultrasound dating by a clinician takes precedence, and nothing here is medical advice.

The site runs entirely in your browser. There is no account, no server-side processing of your dates, and nothing to upload. DueDateCalc is part of a small family of free, single-purpose calculators built by Jimmy | ORBITFRAME.