About calcs.mom

What this is

calcs.mom is a small, ad-free-to-build set of pregnancy and baby calculators — due dates, ovulation, growth percentiles, feeding and sleep tools, and more. We built it because so many calculators online bury a simple estimate under pop-ups, walls of ad copy, or vague "trust us" math with no explanation of where the numbers come from.

Every tool here shows its work: the formula or reference chart behind the result, where that method comes from, and its real-world limits — because a due date or a percentile is an estimate, not a guarantee, and we'd rather you understand it than just believe it.

How the calculators are built

The math behind each tool is based on standard clinical formulas and growth references used by care providers — things like Naegele's rule for due dates, WHO/CDC growth standards for percentiles, and published guidance on newborn feeding and weight. We link to the underlying sources on each calculator page so you can check the method yourself or bring it to your own doctor or pediatrician.

Nothing on this site is medical advice, and none of it replaces a conversation with your OB, midwife, or pediatrician — it's here to help you understand your own numbers before or after that conversation.

Get in touch

Spotted a bug, a confusing result, or a calculator you wish existed? We read every message — corrections especially, since accuracy is the entire point of this site.

Email us