BMI Calculator
Calculate your Body Mass Index, see your BMI category, healthy weight range, and how close you are to optimal.
CalculateHealth & Fitness Calculators
FitUtils is a free hub of science-backed health and fitness calculators. Whether you're tracking body composition, estimating calorie needs, pacing a marathon, checking your aerobic capacity, or timing your sleep — we give you accurate results instantly, with no signup, no ads in your face, and no fluff.
Calorie Calculator
Find how many calories to eat a day to lose, maintain, or gain weight — with your maintenance calories shown too.
CalculateTDEE Calculator
Find your Total Daily Energy Expenditure — the number of calories you burn each day based on your activity level.
CalculateMacro Calculator
Split your daily calories into protein, fat, and carb targets for balanced, high-protein, low-carb, or keto diets.
Calculate1RM Calculator
Estimate your one-rep maximum for any lift using your reps and weight, with the most reliable strength formulas.
CalculateBMR Calculator
Estimate your Basal Metabolic Rate — the calories your body burns at complete rest — and what it becomes at five activity levels.
CalculateCalorie Deficit Calculator
Set a goal weight and a pace, and get the calories to eat each day plus the date you reach it.
CalculateSleep Calculator
Find the bedtime or wake-up time that lands between 90-minute sleep cycles, with a timeline of your night.
CalculateReaction Time Test
Click the moment the panel turns green. Five goes, your average in milliseconds, and how it compares.
Take the testBody Fat Calculator
Body fat percentage from a tape measure or calipers, with your category, fat mass and lean mass.
CalculatePace Calculator
Any two of distance, time and pace give the third — plus splits, equivalent race times and a treadmill converter.
CalculateVO2 Max Calculator
Estimate aerobic capacity from a walk, a run, a step test or your resting pulse, then see your percentile by age and sex.
CalculateLife Expectancy Calculator
An actuarial baseline from CDC life tables, moved by smoking, activity and BMI — with a source beside every year.
CalculateWhy FitUtils?
Always free
No premium plans, no paywalls. Every calculator is free forever.
No signup required
We don't ask for your email. Just open and calculate.
Accurate formulas
Based on WHO, CDC, and peer-reviewed research. No guesswork.
Works everywhere
Fully responsive — works great on any phone, tablet, or desktop.