Sports & Exercise

Three things are often needed when planning training: the intensity you work at, your running pace and the change in body composition. This page estimates them from heart rate, pace and circumference measurements.

Which tool for which question?

• BMR and Daily Calorie Needs Calculator: Calculate your basal metabolic rate (BMR) with the Mifflin-St Jeor equation and your daily calorie needs from your activity level, plus daily calories for a weight loss or gain goal.
• Target Heart Rate Zone Calculator (Karvonen): Estimate your maximum heart rate from your age and the target heart rates for 50–100 % intensity, optionally with your resting heart rate using the Karvonen method.
• Running Pace and Finish Time Calculator: Calculate your running pace per kilometre and average speed from distance and time, or your 5K, 10K, half marathon and marathon finish time from a target pace.
• Body Fat Percentage Calculator (US Navy Method): Estimate your body fat percentage from height, neck, waist and (for women) hip circumference with the US Navy (Hodgdon-Beckett) method, plus fat mass and lean mass.

How the calculation works

• Target heart-rate zones: the tool first finds estimated maximum heart rate by age, then, with the chosen method (such as Karvonen), the heart rates for intensities from 50% to 100%.
• Running pace = time ÷ distance; it works both ways: pace from distance and time, or finish time from distance and target pace.
• Body fat: the US Navy method estimates body density from tape circumference measurements and then fat percentage with the Siri equation.
• Basal metabolism and daily calorie need help plan energy for training days.

Things to watch

• Maximum heart rate is estimated from an age formula and individual differences are large; use the target zones as a guide.
• Fat percentage estimated from circumferences is uncertain compared with laboratory measurement and depends on correct measuring technique.

Results are estimates and do not replace medical advice, diagnosis or treatment; consult your doctor for health decisions.