One Rep Max (1RM) Calculator - Bench, Squat & Deadlift (2026)
Calculate your maximum single-repetition lift (1RM) for bench press, squat, and deadlift using the scientific Brzycki and Epley equations.
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⚙️ Configuration & Inputs
lbs
reps
📊 Results & Analysis
Estimated One Rep Max (1RM)
253 lbs
Brzycki: 253 lbs • Epley: 262 lbs
| 95% of 1RM (1-2 Reps) | 240 lbs |
| 90% of 1RM (3-4 Reps) | 228 lbs |
| 85% of 1RM (5-6 Reps) | 215 lbs |
| 80% of 1RM (7-8 Reps) | 202 lbs |
| 70% of 1RM (10-12 Reps) | 177 lbs |
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Understanding One Rep Max Formulas
Testing true 1-rep maximums to failure poses injury risks. Exercise scientists use sub-maximal predictive formulas:
- Brzycki Formula:
Weight × (36 ÷ (37 - Reps)) - Epley Formula:
Weight × (1 + 0.0333 × Reps)
Frequently Asked Questions
1RM formulas are most accurate when using weights completed for 2 to 6 repetitions. Above 10 repetitions, muscle endurance skews the calculation.