Fitness Calculators
13 free calculators
Performance and training calculators for athletes and fitness enthusiasts.
Heart Rate Zone Calculator
Calculate your 5 heart rate training zones based on your maximum heart rate.
Max HR = 220 − age · Zone % ranges
One Rep Max Calculator
Calculate your one rep maximum (1RM) for any lift using multiple validated formulas.
Epley: 1RM = w × (1 + r/30)
Calories Burned Calculator
Calculate calories burned during exercise based on activity, duration, and body weight.
Calories = MET × weight(kg) × time(h)
VO2 Max Calculator
Estimate your VO2 max — the gold standard of cardiovascular fitness — from running pace.
Jack Daniels running formula
Running Calorie Calculator
Calculate calories burned running based on distance, speed, and body weight.
MET-based running formula
Running Pace Calculator
Calculate running pace, time, or distance. Essential for training and race planning.
Pace = Time ÷ Distance
Steps to Calories Calculator
Convert your daily step count to calories burned based on height, weight, and stride.
MET × weight × time from step count
Muscle Gain Calculator
Calculate your optimal calorie surplus for lean muscle gain, your natural muscle-building potential, and required protein intake.
Surplus = TDEE + 250–500 kcal; Monthly gain by experience level
Fat-Burning Heart Rate Calculator
Calculate your personalised fat-burning heart rate zone (60–70% max HR) and all 5 training zones to optimise cardio for fat loss or performance.
Fat-burn zone = 60–70% of (220 – age)
Target Heart Rate Calculator
Calculate your target heart rate zones for every fitness goal — fat burning, aerobic fitness, anaerobic threshold, and maximum effort.
Target HR = ((HRmax – HRrest) × %intensity) + HRrest
Calories Burned Exercise Calculator
Calculate calories burned during 40+ exercises including running, cycling, swimming, HIIT, strength training, yoga, and walking — personalised by weight.
Calories = MET × weight (kg) × duration (hours)
FFMI Calculator
Calculate your Fat-Free Mass Index — how much muscle you have relative to height. Discover where you sit vs the natural muscle ceiling documented in research.
FFMI = Fat-Free Mass (kg) ÷ Height² (m)
Zone 2 Heart Rate Calculator
Find your Zone 2 heart rate using the Maffetone Method — the aerobic training zone for fat burning, mitochondrial health, and longevity.
Maffetone Method: 180 − Age ± Adjustments
Why Use Fitness Calculators?
Fitness calculators take the guesswork out of your training and nutrition by providing data-driven, personalized targets. Instead of following generic advice, you get numbers calibrated to your specific body, goals, and lifestyle. This is especially important for metrics like TDEE and body fat percentage, which vary enormously between individuals.
Our fitness calculators use the same formulas trusted by certified personal trainers, sports nutritionists, and exercise physiologists — now available to you, for free, in seconds.
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