How to Calculate Your One Rep Max
Quick Answer
Epley formula (most widely used): 1RM = Weight × (1 + Reps ÷ 30)
Brzycki formula: 1RM = Weight ÷ (1.0278 - 0.0278 × Reps)
Example: You lift 80 kg for 8 repetitions.
Epley: 1RM = 80 × (1 + 8 ÷ 30) = 80 × 1.267 = 101.3 kg
Brzycki: 1RM = 80 ÷ (1.0278 - 0.0278 × 8) = 80 ÷ 0.8054 = 99.3 kg
Best accuracy at 3 to 10 repetitions. Use the free One Rep Max Calculator on CalConvs.
Why Calculate 1RM Without Actually Lifting Max?
Attempting a true 1RM requires careful warm-up, a spotter and carries some injury risk. Most coaches calculate estimated 1RM from a submaximal set. The estimate is accurate to within 2 to 5% for most people.
Percentage of 1RM for Training
| % of 1RM | Rep Range | Training Goal |
|---|---|---|
| 100% | 1 rep | Maximum strength test |
| 90 to 95% | 2 to 3 reps | Near maximum strength. Powerlifting competition preparation. |
| 80 to 85% | 4 to 6 reps | Strength training. Core of most strength programmes. |
| 70 to 75% | 8 to 12 reps | Hypertrophy (muscle building). Classic bodybuilding range. |
| 60 to 70% | 12 to 20 reps | Muscular endurance. |
| Below 60% | 20+ reps | Warm-up sets, technique practice. |
Training Load Example (1RM = 120 kg Squat)
- Warm-up sets (50%): 120 × 0.50 = 60 kg
- Strength work (82.5%): 120 × 0.825 = 99 kg (use 100 kg)
- Back-off sets (70%): 120 × 0.70 = 84 kg
Average 1RM Standards by Exercise
| Lift and Level | Standard (multiple of bodyweight) |
|---|---|
| Bench press (beginner men) | 0.5 × bodyweight |
| Bench press (intermediate men) | 1.0 × bodyweight |
| Bench press (advanced men) | 1.5 × bodyweight |
| Squat (intermediate men) | 1.25 × bodyweight |
| Squat (advanced men) | 2.0 × bodyweight |
| Deadlift (intermediate men) | 1.5 × bodyweight |
| Deadlift (advanced men) | 2.5 × bodyweight |
| For women | Approximately 70 to 80% of equivalent men's standards |
Frequently Asked Questions
How accurate is the 1RM calculator?
Estimated 1RM is most accurate when calculated from a set of 3 to 6 repetitions with a weight close to your true maximum. Accuracy decreases at higher rep counts (above 10). The Epley and Brzycki formulas are accurate within 2 to 5% for most people at moderate rep ranges.
How often should I test my 1RM?
Most strength coaches recommend testing or recalculating 1RM every 4 to 8 weeks, aligning with typical training cycles. True 1RM tests are usually saved for competition or the end of a formal training block.
What is the difference between 1RM and training max?
A training max is a conservative version of the 1RM (often 90%) used to calculate programming loads. It builds in a safety margin and ensures progressive overload over multiple training cycles.
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