Health and fitness goals are easier to track when you have the right numbers. These free browser-based calculators give you accurate, evidence-based estimates for the most important health metrics — no app, no subscription, no data collection.
BMI Calculator — Calculate your Body Mass Index from your height and weight. Shows your BMI category (underweight, normal, overweight, or obese) along with the standard ranges. Works with both metric (kg/cm) and imperial (lbs/ft) units.
BMR Calculator — Your Basal Metabolic Rate is the number of calories your body burns at rest. The calculator uses the Mifflin-St Jeor equation (the most accurate formula currently available) and factors in your activity level to give your Total Daily Energy Expenditure (TDEE).
Calorie Calculator — Get a personalized daily calorie target based on your age, sex, height, weight, and activity level. Adjust for weight loss, maintenance, or muscle gain.
Body Fat Calculator — Estimate your body fat percentage using the US Navy circumference method. More accessible than skinfold calipers while still being reasonably accurate.
Water Intake Calculator — Find out how much water you should drink per day based on your weight, activity level, and climate. The 8-glasses-a-day rule is outdated — actual needs vary significantly by person.
Sleep Cycle Calculator — Enter your wake-up time and the calculator gives you the ideal bedtimes to hit a complete number of 90-minute sleep cycles. Waking at the end of a cycle rather than mid-cycle makes a noticeable difference in how rested you feel.
Heart Rate Zone Calculator — Calculate your 5 training zones based on your maximum heart rate. Knowing your zones helps you train smarter — fat-burning, aerobic, and anaerobic work each happen at different intensity levels.
Protein Intake Calculator — Get your recommended daily protein intake based on body weight, activity, and fitness goal (weight loss, maintenance, or muscle building). Backed by current sports nutrition guidelines.
Running Pace Calculator — Calculate pace, distance, or time for any run. Enter two values and get the third. Supports miles and kilometers. Useful for planning training runs and race pacing.
One Rep Max Calculator — Estimate your maximum single-rep lift (1RM) from any training set using the Epley, Brzycki, or Lander formula. Useful for programming strength training percentages.
All calculators are completely free and run in your browser. No account needed and no data is stored.