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. Your inputs and results never leave your device — a calculator shouldn't need your identity to give you an answer. We collect only anonymous usage stats to keep improving the tools (the details).
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.