Free gym calculators for lifters
Quick, accurate calculators for the numbers lifters need between sets: your estimated max, what to load for a target RPE, your 5/3/1 numbers and warm-ups, which plates go on the bar, your powerlifting score, your body fat and how much to eat. No sign-up, no ads, nothing stored.
1RM calculator
Estimate your one-rep max from any set, with five formulas and a full percentage chart.
AutoregulationRPE & RIR calculator
Turn any set at a given RPE into an e1RM, then find the load for your next target reps and RPE.
Gym floorBarbell plate calculator
Which plates go on each side of the bar for any target weight, in kg or lb.
PowerliftingDOTS & IPF GL calculator
Score your squat, bench and deadlift total against your bodyweight with DOTS and IPF GL points.
NutritionTDEE & macro calculator
Estimate your daily calories and protein, fat and carb targets for cutting, maintaining or building muscle.
Programming5/3/1 calculator
Your training max and every set of a full 5/3/1 cycle, rounded to the plates you have.
Gym floorWarm-up set calculator
A ramp of warm-up sets from the empty bar to your working weight, with sensible reps.
Body compositionBody fat calculator
Estimate body fat with the U.S. Navy tape-measure method, plus lean and fat mass.
Run a gym, PT business or coaching site? Put these calculators on your own website for free.
Get embed codesWhy we built these
Gymex is an AI strength-coaching app, and these are the same calculations it runs for you automatically after every set: estimated one-rep max, RPE and Reps in Reserve, and progression targets. The web versions are free for anyone. If you would rather not do the maths yourself, the app logs your sets (including by voice), updates your e1RM and suggests your next weight.