Free, science-backed health calculators. No sign-up required. Instant results you can actually use.
Check your Body Mass Index instantly. Enter your height and weight to see your BMI, category, and what it means for your health.
Calculate your BMI →Find your daily calorie needs (TDEE) using the Mifflin-St Jeor equation. See maintenance, weight loss, and weight gain targets in seconds.
Calculate your calories →Find your daily hydration target based on weight, activity, and climate. Get cups, liters, and an hourly drinking schedule instantly.
Calculate your water intake →Estimate your body fat percentage using the trusted US Navy Method. Enter your measurements for instant results, category, and healthy range comparison.
Calculate your body fat →Calculate your daily protein, carbs, and fat targets based on your goal. Lose weight, maintain, or build muscle — with a full meal timing breakdown.
Calculate your macros →Enter your stats once. Get your complete health profile — BMI, body fat, calories, hydration, and macros — with an overall score from 0 to 100.
Get my health score →Numbers alone don't tell the full story. Explore the research behind each metric.