Health & Fitness Calculators Precision Tools
Free health calculators: BMI, body fat %, calorie needs, protein intake, water intake, sleep cycles, running pace & menstrual cycle. Instant results.
Adult BMI Calculator: Metric and Imperial
Calculate adult BMI from kilograms and centimeters or pounds and inches. See the screening category and understand what BMI can and cannot tell you.
Body Fat Calculator: Circumference Method
Estimate adult body fat with height, neck and waist measurements, plus hips for the female equation. Supports centimeters and inches.
Calorie and Macro Calculator: Custom Planning Targets
Estimate maintenance calories, apply your own calorie adjustment and convert protein, fat and carbohydrate percentages into grams.
Daily Water Intake Calculator: Total Water and Beverages
Compare adult total-water references and estimate the beverage portion after allowing for water in food. Choose your own cup size.
Protein Intake Calculator
Calculate adult or athletic protein references in kg or lb, or enter your own g/kg target.
Sleep Calculator: Bedtime and Wake-Time Planner
Plan bedtime or wake time from a chosen sleep duration and time to fall asleep. Avoid treating every sleep cycle as exactly 90 minutes.
Running Pace Calculator: Pace, Time and Distance
Solve for running pace, elapsed time or distance. Compare minutes per kilometer and mile with consistent rounding.
Period Calculator: Next Date and Six-Cycle Calendar
Project upcoming period dates from your last start date and average cycle length. See a calendar estimate without false ovulation certainty.
BRI Calculator: Body Roundness Index
Calculate body roundness index and waist-to-height ratio from centimeters or inches, with the formula and its limits explained.
BMR Calculator: Resting Calorie Estimate
Estimate resting energy expenditure with the Mifflin–St Jeor equation using metric or imperial measurements.
TDEE Calculator: Maintenance Calorie Estimate
Estimate daily maintenance calories from resting energy and an explicit activity multiplier. Compare assumptions without automatic diet targets.
Calorie Deficit Calculator: Intake from Maintenance
Calculate the intake implied by a maintenance estimate and a daily calorie deficit, without promising a weight-loss date.
Pregnancy Due Date Calculator: LMP, Conception and IVF
Estimate a due date using your last period, a known conception date, or a day-3 or day-5 embryo transfer.