LeanCalc is a free collection of science-backed health calculators. No accounts. No paywalls. No upsells before you see your results. Just accurate tools that help you understand your body and reach your goals.
Every calculator on LeanCalc uses validated, peer-reviewed formulas — the same ones used by dietitians and fitness professionals. We explain the science behind every output so you understand your numbers, not just receive them.
LeanCalc is supported by display advertising through Google AdSense. Ads appear after you have already seen your results — never before. We keep the experience clean and the tools fast.
Our calorie and TDEE calculations use the Mifflin-St Jeor equation — the most validated BMR formula for general adult populations according to the Academy of Nutrition and Dietetics. BMI uses the standard WHO formula. Protein targets are based on ranges from the International Society of Sports Nutrition. Water intake uses a weight-based formula adjusted for activity and climate.
All results are estimates. Individual results vary based on genetics, health conditions, and other factors. Always consult a healthcare provider before making significant changes to your diet or exercise routine.
Questions, feedback, or partnership enquiries — we would love to hear from you.
Email: support@leancalc.com