Estimate your one-rep max (1RM) from any weight and rep count, plus training percentages for programming.
Your one-rep max (1RM) is the maximum weight you can lift for a single repetition of an exercise. It is the gold standard for measuring strength and the foundation of most percentage-based training programs. Rather than testing a true max (which is risky and fatiguing), our calculator estimates it from a set you have already performed.
We average two of the most respected formulas — Epley and Brzycki — to give a reliable estimate across a wide range of rep counts.
Serious programs prescribe weights as a percentage of your 1RM. Working at 70% builds volume and hypertrophy, 80% develops strength, and 90%+ trains raw power. Knowing your 1RM lets you follow proven programs like 5/3/1 or Starting Strength without guessing.
Re-test your estimated 1RM every 4–6 weeks to keep your working percentages accurate as you get stronger.
Estimates are most accurate at lower rep ranges (1–6 reps). Above 10 reps, fatigue skews the numbers. Always warm up thoroughly, use a spotter for heavy pressing, and never sacrifice form for a higher number. Fuel those lifts with enough calories and protein to recover and grow.