Free Health & Fitness Calculators
Tracking progress is more motivating when you have a few honest numbers to work with. The BMI calculator gives a quick screening figure from height and weight in metric or imperial units. The calorie calculator estimates how much energy you burn each day based on age, size and activity level, which is a useful starting point when planning meals for maintenance, a gradual cut or a muscle-building phase. The body fat calculator uses tape measurements to estimate composition without special equipment.
During training, the stopwatch and timer handles intervals, rest periods and timed holds without a dedicated app. The reaction time test is a fun way to check how alert you are before a game or after a poor night's sleep, and to watch improvements over weeks. All of these run in the browser and nothing you type is saved unless you choose to sign in. For anything beyond a rough estimate, check in with a doctor, dietitian or qualified coach.
Results are estimates, not medical advice.
Body & nutrition
Training & reflexes
Frequently asked questions
- How accurate are these calculators?
- They use standard published formulas, which work well for most adults but cannot account for every body. Treat the numbers as estimates.
- Why does BMI not match how fit I feel?
- BMI does not separate muscle from fat, so athletes often score higher than their body composition suggests. Body fat estimates add useful context.
- Can I use the stopwatch for interval training?
- Yes. Use the countdown timer for work and rest periods, and the stopwatch with laps to time sets or runs.