Blood Alcohol Calculator
Estimate your BAC with the Widmark formula.
Health & Fitness
BMR, calories, heart-rate & body metrics.
BMR Calculator
Estimate resting calories burned per day.
Body Fat Percentage Calculator
Estimate body fat from tape measurements.
Body Surface Area Calculator
Estimate body surface area with four formulas.
Calories Burned Calculator
Estimate calories burned from activity and time.
Daily Calorie Needs Calculator
Daily calories for your goal, with macros.
Heart Rate Zone Calculator
Find your five training heart-rate zones by age.
Ideal Weight Calculator
Estimate ideal body weight four ways from height.
Lean Body Mass Calculator
Estimate your lean body mass and fat mass.
Macro Nutrient Calculator
Turn a calorie target into protein, carb and fat grams.
Max Heart Rate Calculator
Estimate your max heart rate from age, four ways.
Ovulation Calculator
Estimate your fertile window and ovulation day.
Pace to Finish Time
Predict your race finish time from your pace.
Pregnancy Weight Gain Calculator
Check pregnancy weight gain against IOM guidelines.
Protein Intake Calculator
Estimate your daily protein target.
Smoking Cost Calculator
See what smoking really costs over time.
TDEE Calculator
Find your daily calories to cut, maintain or bulk.
VO2 Max Estimator
Estimate your aerobic fitness from a simple test.
Waist to Hip Ratio
Measure body-fat distribution and health risk instantly.
Water Intake Calculator
Estimate how much water to drink each day.
About Health & Fitness
Estimate the numbers behind training and nutrition: BMR and TDEE for daily calorie needs, macro splits, body-fat percentage from tape measurements, heart-rate training zones, running pace, VO2 max and more. Each calculator names the published formula it uses (Mifflin-St Jeor, Katch-McArdle, Karvonen and others) so you know exactly where the estimate comes from. Health data is about as personal as data gets — which is why every calculation here runs locally in your browser and nothing you enter is uploaded, logged or stored. These tools give estimates for healthy adults and are not a substitute for medical advice.