Health & Fitness
One Rep Max Calculator
Estimate your one-rep max from a set you can already do — no risky max-out needed — using the Epley and Brzycki formulas, with a training-load table for every rep range.
Most accurate at 10 reps or fewer.
Estimated one-rep max
117 kg
Epley
117 kg
Brzycki
113 kg
Training loads (% of 1RM)
How to use the one-rep max calculator
Enter the weight you lifted and how many clean reps you managed with it — ideally a set of 3 to 8. The calculator estimates your one-rep max two ways and shows the weight to use for any rep target. Recalculate every few weeks as you get stronger.
The formulas
Epley: 1RM = weight × (1 + reps ÷ 30)
Brzycki: 1RM = weight × 36 ÷ (37 − reps)
Example. Lifting 100 kg for 5 reps gives an estimated 1RM of about 117 kg by Epley (or 113 kg by Brzycki). From there, roughly 80% — about 91 kg — is a good weight for sets of 8.
Frequently asked questions
Your one-rep max (1RM) is the heaviest weight you can lift for a single, full repetition of an exercise. It is the standard measure of maximal strength, and most training programmes set working weights as a percentage of it.