Calculators and timers for training

Run the numbers, then run the clock

Body composition, calorie, strength and running calculators next to the timers you actually use in the gym — with formulas, sources and no sign-up. Everything runs in your browser.

Calculators · 13 Timers · 10

Body composition

Body Mass Index (BMI) Weight-to-height ratio with WHO categories and your healthy weight range Body fat percentage US Navy method: neck, waist and hips instead of calipers Ideal weight Six classic formulas plus the healthy BMI range FFMI — fat free mass index How much muscle you carry and where the natural ceiling sits

Calories and nutrition

Calorie needs Basal rate, daily expenditure and your target intake Macros — protein, fat, carbs Splitting your calories into macronutrients for your goal Daily water intake Adjusted for training volume and hot weather

Strength training

One rep max (1RM) Seven formulas, a percentage table and working weights for any rep range Barbell plate loader What to load on each side, plus a warm-up ramp Wilks, DOTS and IPF GL Points Comparing lifters across body weights with three scoring systems

Running

Heart rate zones Five zones by max heart rate and by Karvonen reserve Running pace Pace, speed, time and distance with a kilometre split table Race time predictor Riegel and Cameron: your result projected onto other distances

Timers

Basic

Stopwatch With laps and split times Countdown timer A simple timer for a set duration Rest between sets Presets for 60, 90, 120 and 180 seconds

Interval

Tabata 20 seconds on, 10 off, 8 rounds Interval timer (HIIT) Build your own: work, rest, rounds and cycles EMOM Every minute on the minute: work, then rest what is left AMRAP As many rounds as possible in the time cap

Combat sports

Round timer Boxing, MMA, wrestling: rounds with breaks and a warning bell

Strength

Plank and isometrics Timed holds with sets and rest

Breathing and recovery

Box breathing Inhale, hold, exhale, hold — four seconds each