Fitness & SportsStrength
1-Rep Max (1RM) Strength Benchmark Calculator
Estimate your 1-Repetition Maximum (1RM) safely without testing to failure. Generates full workout percentage tables from 1 to 12 repetitions.
Completed Strength Set
Reps Completed Cleanly6 Reps
Estimated 1-Rep Maximum (1RM)
265 lbs
Average of Brzycki (261.3 lbs) and Epley (270 lbs) formulas
Training Repetition Ranges:
265 lbs
1RM (100%)
251.8 lbs
2RM (95%)
246.5 lbs
3RM (93%)
238.5 lbs
4RM (90%)
230.6 lbs
5RM (87%)
225.3 lbs
6RM (85%)
Mathematical Formula: Brzycki & Epley 1RM Formulas
Epley: 1RM = W · (1 + 0.0333 · r) | Brzycki: 1RM = W · [36 / (37 - r)]
Predicts maximum single-effort lifting capacity from submaximal repetitions (1 to 10 reps).
How to Use This Calculator
- 1Enter the weight lifted (in kg or lbs).
- 2Enter the number of completed repetitions performed with clean form (best accuracy between 2 and 10 reps).
- 3Review your estimated 1RM and customized percentage training table (95%, 90%, 85%, 80%, etc.).
Practical Example: Bench Press Set of 225 lbs for 6 Reps
Scenario: Lifting 225 lbs for 6 clean repetitions.
Weight:225 lbs
Reps:6
Result: Estimated 1RM: 265.5 lbs | 5RM (87%): 231.0 lbs | 10RM (75%): 199.1 lbs
A 6-rep set at 225 lbs corresponds to an estimated single maximum lift of ~265 lbs.
Frequently Asked Questions
Calculating 1RM from a heavy set of 3 to 5 reps avoids the high joint stress and injury risk of lifting a true 100% max single.
Pro Calculation Tips
- Use the 70% - 85% 1RM ranges for optimal hypertrophy muscle-building sets.
Model Assumptions
- Formulas lose accuracy when rep counts exceed 10 to 12 repetitions.