A familiar situation
Estimate a training load from a submaximal set without treating the result as a tested maximum.
How to use this calculator
- Enter weight lifted, repetitions completed, estimate formula.
- Select Calculate to see the answer and its breakdown.
- Keep a scenario, change an input and compare the results.
Use consistent units and check the assumptions below before applying the result.
How one rep max is calculated
Epley: 1RM = load×(1+reps/30). Brzycki: 1RM = load×36/(37−reps). Both are estimates and become less dependable at high repetition counts. A 100 kg set of 5 reps estimates about 116.7 kg by Epley and 112.5 kg by Brzycki.
Epley=load×(1+reps/30); Brzycki=load×36/(37−reps).A 100 kg set of 5 reps estimates about 116.7 kg by Epley and 112.5 kg by Brzycki.
Assumptions & useful context
Prediction only; it is not a tested maximum or a safety recommendation.
Health calculations are estimates for education. They cannot diagnose a condition or replace a clinician’s assessment. Individual needs vary, especially during pregnancy, illness and growth.
Frequently asked questions
Should I attempt the estimated maximum?
Not based on this number alone; use safe technique, suitable supervision, and your training context.
Why do formulas disagree?
They fit different observed lifting data and approximate the strength-repetition relationship differently.