Health Calculators
BMI, calorie need, body fat percentage, and pregnancy tools. Every formula cites its medical reference — WHO, Mifflin-St Jeor, US Navy method.
Available now
Body Mass Index with metric and imperial units. Instant category lookup against WHO ranges.
Basal Metabolic Rate via Mifflin-St Jeor. Shows calories burned at rest + activity multipliers.
Total Daily Energy Expenditure with activity level. See maintenance calories and macro targets.
Daily calorie target for weight loss, maintenance, or muscle gain. With estimated timeline.
Coming soon
US Navy method using neck, waist, and hip measurements.
Due date and pregnancy milestones from last menstrual period.
About Calctube health tools
Calctube's health calculators target the most-searched fitness and clinical estimators on the web — BMI, calorie need, BMR, body fat percentage, TDEE, and pregnancy due date. Every page shows the exact formula and the medical reference behind it. Calculations run in your browser; we never see or store your inputs.
These tools are designed for healthy adults and produce reasonable estimates only. They are not a substitute for clinical assessment, prescription, or diagnosis by a qualified physician.
Frequently asked questions
Are Calctube health calculators medically accurate?
Our formulas are sourced from established medical references — WHO BMI ranges, Mifflin-St Jeor for BMR, US Navy for body fat. They produce reasonable estimates for healthy adults but are not a substitute for clinical assessment by a doctor.
Why does the BMI calculator give different categories for the same weight?
BMI categories depend on the population standards selected. We default to WHO global ranges (underweight <18.5, normal 18.5–24.9, overweight 25–29.9, obese 30+). Asian populations use stricter cutoffs (overweight 23+, obese 27.5+) per WHO Asia-Pacific guidance — toggle this on the BMI page.
Do you store any of my health data?
No. All calculations run entirely in your browser. We never see your height, weight, age, or any other input. There is no account or login.