One Rep Max (1RM) Calculator

Estimate your maximum single-rep lift based on the weight and reps you can perform.

Measurement System:
lbs
reps
Estimated One Rep Max
253 lbs
95% (Heavy Single)
240
1-2 reps
90% (Strength)
228
2-3 reps
80% (Hypertrophy)
202
5-8 reps
70% (Endurance)
177
10-15 reps

Training Load Chart

% Weight Rep Range Training Goal

Understanding Your 1RM

What is a 1RM? Your One Rep Max is the maximum weight you can lift for a single repetition with proper form. It's a key metric for measuring strength and programming training.

How to use it: Rather than testing your actual 1RM (which can be risky), use the percentages above to plan your workouts. For strength, work at 85-95%. For muscle building, 65-85%. For endurance, 50-65%.

References: Brzycki Formula, Epley Formula, National Strength and Conditioning Association (NSCA).