Tiny health tools, calculated instantly.
Free, no-signup calculators for everyday health and fitness questions. Every number comes with a short explanation of what it means — and what it doesn’t.
Calculators
TDEE Calculator
Estimate your total daily energy expenditure and calorie targets for maintenance, cutting, or bulking.
CalculatorProtein Intake Calculator
Find a protein range tailored to your body weight, body composition, and training goal.
CalculatorHeart Rate Zones
Calculate aerobic training zones using the Karvonen formula and your resting heart rate.
CalculatorCaffeine Half-Life
See how much caffeine is left in your system hour by hour, including at bedtime.
CalculatorSleep Cycle Calculator
Find bedtime or wake-up times based on 90-minute sleep cycles and a fall-asleep buffer.
CalculatorWater Intake Calculator
Estimate daily fluid needs from body weight, exercise, and climate.
CalculatorFFMI Calculator
Estimate fat-free mass index from weight, body fat, and height.
CalculatorCreatine Dose Calculator
Get maintenance and optional loading-phase dosing based on body weight.