Founder & Builder
Mohtashim
I build calculators that show their work. Every tool on Numexa runs on a formula from a published source, proven by automated tests before it ships, and explained with the sources on the page — so you never have to take a number on faith.
Why Numexa exists
The internet's most-used calculators are stuck in the past — cramped layouts, walls of ads, and answers with no explanation of where the math comes from. I didn't think "trustworthy" and "pleasant to use" should be a trade-off. So I built Numexa: calculators that answer instantly, look good doing it, and can prove every number.
The standard every calculator must pass
- The formula comes from the primary source. Mifflin-St Jeor for metabolism, Naegele's rule for due dates, the IOM 2009 guidelines for pregnancy weight gain, the U.S. Army's AR 600-9 tape method — named, cited, and implemented exactly as published.
- Automated tests prove it. 249 tests check every formula against reference values from its published source. If a single test fails, the tool doesn't ship. Change anything, and the whole suite runs again.
- Results are cross-checked. Outputs are verified against established references, so a Numexa answer never stands alone.
- Sources are on the page. 102 citations across the site — 25 of them to peer-reviewed research on PubMed, alongside the WHO, CDC, ACOG, the National Academies, Mayo Clinic and NHS. Every health claim links to where it came from.
What I don't claim
I'm not a doctor, and Numexa doesn't pretend otherwise. What I'm rigorous about is the math: the right formula, from the right source, implemented correctly and tested continuously. Numexa is information — not medical advice. For decisions about your health, talk to a clinician who can see the whole picture.
Privacy, by design
Numexa has no accounts and stores none of your data. Your inputs stay on your device — a calculator shouldn't need your identity to give you an answer.
Spotted something off?
Accuracy is the whole product, so I treat error reports as gifts. Reach me through the contact page — every report gets read.