What Is One Rep Max?
One Rep Max (1RM) is the maximum amount of weight you can lift for a single repetition with proper form. It is the gold standard for measuring absolute strength in a given exercise. Knowing your 1RM is essential for programming training loads, as most strength and hypertrophy programs prescribe weights as percentages of your 1RM.
Directly testing your 1RM can be risky and requires extensive warm-up and spotters. Estimation formulas provide a safer alternative by predicting your 1RM from submaximal lifts. These formulas are most accurate when using loads that allow between 2 and 10 repetitions, as higher rep sets introduce more fatigue variables.
1RM Formulas
Training Percentages
| % of 1RM | Reps | Training Goal |
|---|---|---|
| 90-100% | 1-3 | Maximal Strength |
| 80-89% | 3-6 | Strength |
| 70-79% | 6-12 | Hypertrophy |
| 60-69% | 12-20 | Muscular Endurance |
| 50-59% | 20+ | Warm-up / Recovery |
Frequently Asked Questions
Which 1RM formula is most accurate?
The Epley and Brzycki formulas are most widely used and produce similar results for moderate rep ranges (3-10 reps). Brzycki tends to be slightly more conservative. For very low reps (2-3), both are quite accurate; accuracy decreases with higher rep sets.
How often should I test my 1RM?
Most programs recommend testing every 8-12 weeks at the end of a training cycle. Frequent 1RM testing adds fatigue and injury risk without providing proportional benefit. Using estimation formulas weekly with your working sets is a safer way to track progress.
Does 1RM differ by exercise?
Yes, 1RM is exercise-specific. Your bench press 1RM will differ from your squat or deadlift. Each exercise should be estimated independently based on that exercise's performance.