HealthCheck is a collection of 52 health and fitness calculators. Body fat, BMI, TDEE, macros, calorie deficit planning, and dozens more. Each one runs a published, peer-reviewed formula on the numbers you type in, and gives you a result you can actually use.
That is the whole idea. No accounts required, no paywalls, no selling your data. The calculations happen in your browser. We built the site because most online health calculators are either buried in ads or use outdated equations, and we thought that was a solvable problem.
Every calculator cites the specific formula it uses. Body fat estimation relies on the U.S. Navy circumference method, Jackson-Pollock skinfold equations, or BMI-derived correlations depending on what inputs you provide. Energy expenditure calculations use the Mifflin-St Jeor equation, which a 2005 meta-analysis in the Journal of the American Dietetic Association found to be the most accurate predictive equation for resting metabolic rate in healthy adults.
We pick formulas based on what the research actually supports, not what is easiest to implement. When a newer study supersedes an older method, we update. The Mifflin-St Jeor equation replaced Harris-Benedict here years ago for exactly that reason.
These are still estimates. A DEXA scan will always beat a circumference formula. If you are making medical decisions, talk to a doctor who can order proper lab work. Our calculators are a good starting point, not a diagnosis.
Three subject-matter reviewers check our calculator logic, result interpretations, and blog posts before they go live.
Sarah Chen, MS, CSCS reviews exercise science content. She has a Master of Science in Exercise Physiology from the University of Florida and is an NSCA-certified Strength and Conditioning Specialist with over eight years of experience in clinical exercise testing and sports performance.
James Morton, RD, CSSD handles nutrition and dietetics. He is a Registered Dietitian and Board Certified Specialist in Sports Dietetics who spent five years in hospital clinical nutrition before moving into sports and public health nutrition.
Lisa Patel, PhD, CPH covers public health and epidemiology. She earned her doctorate in Epidemiology from Emory University and holds a Certified in Public Health credential. Her research focused on population-level body composition metrics and mortality risk prediction.
You can read more about our review process on the editorial standards page.
Your numbers stay in your browser. Calculations run client-side. We do not send your height, weight, or any other inputs to a server unless you explicitly choose to save results to an account. If you do create an account, your saved data is protected by row-level security so only you can access it. We do not sell or share user data.
Here are some of the most-used ones:
Estimate body fat percentage using Navy, Jackson-Pollock, or BMI methods
Calculate your Body Mass Index with WHO and CDC classifications
Find your Total Daily Energy Expenditure via Mifflin-St Jeor
Set a daily calorie target based on your TDEE and weight goal