Body mass index, body fat percentage by the US Navy tape method, TDEE and the calorie target implied by a chosen deficit, bedtimes aligned to sleep cycles, and an estimated due date from a last menstrual period.
These are estimates built on population averages, and each page says where its formula comes from and where it breaks down — BMI famously misclassifies muscular people, TDEE varies by 200+ calories a day between individuals with identical stats. That caveat is part of the tool rather than fine print, because a number without its error bars is worse than no number.
All health & fitness tools
- BMI Calculator — Body mass index with metric or imperial units.
- Body Fat Calculator — Estimate body fat % with the US Navy tape method.
- Calorie Deficit Calculator — TDEE, target intake and weekly loss from a chosen deficit.
- Sleep Calculator — Bedtimes and wake-up times aligned to 90-minute sleep cycles.
- Due Date Calculator — Estimated due date, current week and trimester from your LMP.
Frequently asked questions
How accurate are these calculators?
Accurate as estimates, not as measurements. BMI is a population screening tool that says nothing about body composition. The Navy body-fat method is typically within about 3–4 percentage points of a DEXA scan. TDEE formulas are averages that individuals vary meaningfully around. Use them to track direction over weeks, not to make decisions off a single reading.
Is my health data sent anywhere?
No. Everything is computed in your browser and nothing — height, weight, measurements, dates — is transmitted or stored. Given what these inputs reveal, that's the only reasonable way to build them.
Should I use these instead of seeing a doctor?
No. They're for orientation and tracking, not diagnosis. Anything that concerns you — an unexpected result, a symptom, a pregnancy — belongs with a clinician who can examine you and knows your history.