About FemiFitCalc
FemiFitCalc is a free hub of 32 fitness, nutrition and women's health calculators. We believe a health number is only useful when you understand where it comes from — so every tool shows its formula and a worked example.
Science-based formulas
Every calculator uses a published method — WHO BMI categories, Mifflin-St Jeor, the U.S. Navy circumference method, Naegele’s rule, the Tanaka heart-rate formula and more — and shows you the math.
Private by design
Everything runs in your browser. Your measurements, dates and results are never sent to a server, never stored in an account and never shared.
Built for women first
Alongside general fitness and nutrition tools, we give cycle, ovulation and pregnancy calculators the same care and prominence — not an afterthought.
Who runs FemiFitCalc
FemiFitCalc is an independent project run by one person. The site is currently free to use and contains no advertising.
Questions, corrections or feedback? Email [email protected].
How we choose our formulas
Every formula on this site is a published method — not something we invented. We use consensus public-health standards and widely referenced equations, including WHO BMI categories, the Mifflin-St Jeor equation for resting metabolism, the U.S. Navy circumference method for body fat, the Devine, Robinson, Miller and Hamwi ideal weight equations, Naegele’s rule, Tanaka’s age-predicted maximum heart rate, the Epley and Brzycki one-rep-max equations, and the EFSA and Institute of Medicine hydration reference intakes.
Each page shows the formula it uses, a worked example, a visible “Last updated” date and a Sources section that points to the organisation or peer-reviewed paper behind it — the World Health Organization, the US CDC, the NIH, EFSA, ACOG, the NHS, academic journals and others. The math on the page is the method its sources describe, so you can check the numbers yourself.
Privacy and how your data is handled
All calculations run entirely in your browser. We do not ask you to create an account, and your measurements, dates and results are not stored on our servers. Emails you send to us are used only to reply to your message.
Calorie, macro and medical-looking estimates on this site are informational only and never replace advice from a qualified healthcare provider.
FemiFitCalc is an informational tool, not a medical service. Our content is written for general education and reviewed against public health references such as WHO BMI categories and ACE body-fat guidelines.
Explore the calculators