Health & Fitness Calculators

These free calculators will help you to track your weight, measure your fitness and more.

Health and fitness numbers only become useful when you can interpret them. A single BMI number means little without context — your body composition, age, and goals matter more than the raw figure. Calorie targets depend on activity, basal metabolic rate, and whether you're maintaining, losing, or gaining weight. Body fat percentage depends on the measurement method, and methods disagree.

These calculators give you the numbers and the context. Calculate your BMI, BMR, calorie needs, body fat percentage, ideal weight range, or how many calories specific activities burn — using formulas validated in the research literature. Each result is paired with explanations of what the number means, when it's reliable, and where its limitations are. Browse the calculators below, or pick one of the popular tools above.

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FAQs

BMI is useful as a population-level screening tool but can mislead for individuals. Athletes with high muscle mass often register as overweight or obese by BMI despite low body fat. Older adults can have a normal BMI while carrying high visceral fat. Treat BMI as a starting signal, not a final diagnosis — combine it with waist-to-hip ratio, body fat percentage, and how you feel.

A daily deficit of 300-500 calories below your maintenance level (your TDEE) typically produces 0.5-1 pound of fat loss per week — a sustainable pace for most people. Larger deficits work short-term but tend to backfire through muscle loss, hunger, and rebound eating. Calculate your TDEE first, then subtract.

BMR (Basal Metabolic Rate) is the calories your body burns at complete rest, just to keep organs running. TDEE (Total Daily Energy Expenditure) is BMR plus everything else — activity, exercise, even digesting food. TDEE is the figure you want for setting calorie targets; BMR is one input that goes into calculating it.

Monthly is plenty for most people. Daily measurements are noisy — weight fluctuates 2-5 pounds within a day from water and food alone, and most measurement methods have an error margin larger than typical week-to-week change. Look at the trend over weeks, not the daily reading.

No. They provide useful estimates based on validated formulas, but they don't account for medical conditions, medications, pregnancy, or individual physiology. For any health concern — significant weight change, body composition shifts, or fitness goals tied to a medical condition — talk to a doctor or registered dietitian.