Estimate your 1RM from a submaximal set and get a full percentage training table.
One rep max is the gold standard for measuring strength, but testing it directly carries injury risk, especially for beginners. Submaximal testing (lifting a manageable weight for a moderate number of reps) combined with a predictive formula is safer and correlates well with actual 1RM for 1–10 repetitions. The three formulas shown have different mathematical shapes, so their average reduces systematic bias from any single model. Use the resulting 1RM to set training loads: 70–80% for hypertrophy, 80–90% for strength, >90% for maximal strength development.
Epley (1985)
1RM = Weight × (1 + Reps/30)
Brzycki (1993)
1RM = Weight × 36 / (37 − Reps)
Lombardi (1989)
1RM = Weight × Reps^0.1
1RM estimates are mathematical predictions, not substitutes for proper progression programming or coaching. Attempting maximum or near-maximum lifts without appropriate training history, technique, and supervision carries injury risk. Always train safely.
3–6 reps gives the most accurate prediction. At 1–2 reps the result is almost your actual 1RM. At 10+ reps neural efficiency and muscular endurance become confounding factors, making the estimate less reliable.
No — the formula is unit-agnostic. Enter your weight in whatever unit you use and the result will be in the same unit.
If you're new to heavy lifting, don't. The estimate is a planning tool, not a mandate. Work up to 90–95% of your predicted 1RM for training cycles before testing the actual maximum. Always have a spotter for maximal or near-maximal attempts.