Fitness & Exercise Calculators
Plan your training and track your progress — work out running pace and race times, estimate your one-rep max, find your heart-rate zones, gauge VO2 max and count the calories you burned. Every tool uses a recognised exercise-science formula and runs entirely in your browser.
- Running Pace Calculator Enter any two of pace, time and distance, and get the third
- Pace Converter (min/km, min/mile, mph, km/h) Convert a pace or speed between min/km, min/mile, km/h and mph
- One-Rep Max (1RM) Calculator Enter a weight and the reps you managed to estimate your one-rep max
- Heart Rate Zone Calculator Enter your age to get your five training heart-rate zones
- Race Time Predictor Enter one recent race time and get predicted times
- VO2 Max Calculator (Cooper Test) Do the Cooper test
- Calories Burned Calculator Pick an activity, enter your weight and how long you did it, and get an estimate of the calories you burned
- Steps to Distance Calculator Turn a step count into distance in kilometres and miles
- Swimming Pace Calculator Enter the distance you swam and your time to get your pace per 100 m and per 100 yd.
- Calorie Deficit Calculator Enter how much weight you want to lose and over how many weeks to get the daily calorie deficit required.
Frequently asked questions
Are these fitness calculators accurate?
They use established exercise-science formulas — Epley/Brzycki/Lombardi for one-rep max, Tanaka/Karvonen for heart rate, Riegel for race prediction, Cooper for VO2 max, and the ACSM MET equation for calories — each cited on its tool page. Formula estimates are population-based, so treat them as guides, not lab measurements.
Do they work in metric and imperial?
Yes — paces show in both min/km and min/mile, weights toggle between kg and lb, and distances handle km and miles.
Is my data uploaded?
No. Every tool runs entirely in your browser — nothing is sent to a server, and they work offline.
Is this medical advice?
No. These are general fitness tools for training and tracking, not medical advice. Check with a doctor before starting hard exercise or a maximal test if you have any health concerns.