Fitness and Health Calculators
Body composition, calorie needs, pregnancy, athletic performance, nutrition macros, and more. Every calculator uses validated clinical formulas and shows exactly how the result was computed.
How to Use These Calculators
Each calculator on this page uses one or more validated clinical or research formulas. The results are estimates based on population averages. Individual variation in metabolism, genetics, body composition, and health status means any calculated value is a starting point, not a precise measurement.
For body composition goals
Start with the BMI Calculator to understand where you currently fall in weight categories, then use the Body Fat Calculator for a more precise measure of composition. The Calorie and TDEE calculators together give your energy baseline - from there the Macro Calculator divides that total into protein, carbs, and fat targets appropriate for your goal.
For fitness and athletic performance
The Target Heart Rate Calculator defines your training zones for aerobic and anaerobic work. The Pace Calculator helps structure runs for races from 5K through marathon. The One Rep Max Calculator is essential for progressive overload programming. The Calories Burned Calculator helps quantify the energy cost of your workouts and keeps dietary adjustments on track.
Understanding the Key Metrics
BMI
Body Mass Index is weight in kilograms divided by height in metres squared (kg/mยฒ). The WHO classifies below 18.5 as underweight, 18.5 to 24.9 as normal weight, 25 to 29.9 as overweight, and 30 and above as obese. Asia-Pacific classifications use lower thresholds: overweight begins at 23 and obesity at 27.5. BMI does not distinguish between muscle and fat mass.
BMR and TDEE
Basal Metabolic Rate is the number of calories the body burns at complete rest just to maintain life. TDEE multiplies BMR by an activity factor (1.2 for sedentary to 1.9 for very active) to estimate total daily caloric needs. Eating below TDEE creates a caloric deficit for weight loss; above creates a surplus for muscle gain.
Body Fat Percentage
More informative than BMI, body fat percentage distinguishes between lean mass (muscle, bone, water) and fat mass. Essential fat is about 3 to 5% for men and 11 to 13% for women. Athletic ranges are 6 to 13% for men and 14 to 20% for women. Above 25% for men and 32% for women is considered obese.
| Category | Men | Women |
|---|---|---|
| Essential fat | 3 to 5% | 11 to 13% |
| Athletes | 6 to 13% | 14 to 20% |
| Fitness | 14 to 17% | 21 to 24% |
| Acceptable | 18 to 24% | 25 to 31% |
| Obese | 25%+ | 32%+ |