Running & pace
4Running Pace Calculator
Enter any two of distance, time and pace — get the third instantly, in min/km and min/mile.
Open toolPace Calculator
Work out the pace you need to hold to hit a target finish time over any distance.
Open toolVO2 Max Estimator
Estimate your VO2 max from a 12-minute Cooper test or a 1.5-mile run time.
Open toolSwimming Pace Calculator
Convert a swim time and distance into pace per 100 m and per 100 yd.
Open toolBody & weight
4BMI Calculator
Calculate your Body Mass Index in metric or imperial and see your category.
Open toolBody Fat Calculator
Estimate body fat percentage with the US Navy tape method — no calipers needed.
Open toolBody Fat Percentage Calculator
Estimate your body fat percentage and see how it maps to athlete, fitness and average ranges.
Open toolIdeal Weight Calculator
Estimate a healthy weight range using the Devine, Robinson and Hamwi formulas plus the BMI range.
Open toolCalories & nutrition
7Calorie Calculator (TDEE)
Estimate your daily calorie needs for maintenance, loss or gain, based on your activity level.
Open toolCalories Burned Calculator
Estimate calories burned for dozens of activities using MET values and your bodyweight.
Open toolCalorie Burn Calculator
Quickly compare how many calories different workouts burn for your bodyweight.
Open toolBMR Calculator
Find your Basal Metabolic Rate — the calories you burn at complete rest — using the Mifflin-St Jeor equation.
Open toolProtein Calculator
Work out your daily protein target based on bodyweight and goal.
Open toolProtein Intake Guide
How much protein you need, when to eat it, and the best sources — with a quick calculator.
Open toolWater Intake Calculator
Estimate your daily fluid needs from bodyweight, activity and climate.
Open toolHeart rate & training
4Heart Rate Zone Calculator
Find your five training zones using max heart rate, with optional Karvonen (resting HR) accuracy.
Open toolTarget Heart Rate Calculator
Find the heart-rate range to aim for during exercise based on your chosen intensity.
Open toolMax Heart Rate Calculator
Estimate your maximum heart rate with several validated formulas side by side.
Open toolWorkout Interval Timer
A free HIIT / Tabata interval timer — set work, rest and rounds, with audio cues.
Open toolStrength & reference
4One Rep Max Calculator
Estimate your 1RM from a set, and get your full percentage training table.
Open toolOne-Rep Max (1RM) Chart
Quick 1RM estimate plus a printable percentage chart for every main lift.
Open toolStep Counter Converter
Convert steps to distance and calories, or work out the steps for a target distance.
Open toolExercise Library
A searchable library of common exercises by muscle group and equipment.
Open tool