One-Rep Max Calculator
Calculate your estimated one-rep maximum using proven formulas from strength training research. Perfect for powerlifting, weightlifting, and strength programming.
1RM Calculation
Enter your lift weight, repetitions, and select a formula to calculate your one-rep max
reps (1-10)
1RM = W × (1 + r ÷ 30)
Most commonly used, good for 1-10 reps
1RM = W × 36 ÷ (37 − r)
Conservative estimate, best for 2-10 reps
1RM = W × r^0.10
Based on power function, good for all rep ranges
Estimated 1RM
Enter weight and reps to calculate your one-rep max.
About One-Rep Max Testing
Formula Comparison
- Epley: Most popular, linear progression
- Brzycki: More conservative, asymptotic curve
- Lombardi: Power function, works across all rep ranges
- Accuracy: All formulas are within ~10% of actual 1RM
Best Practices
- Use weights you can lift for 3-8 reps for best accuracy
- Ensure proper form throughout the test set
- Rest adequately between attempts
- Test when fresh, not after other training
Safety Considerations
- Warm-up: Always perform proper warm-up sets
- Spotter: Use a spotter for bench press and squats
- Progressive: Work up gradually to test weight
- Recovery: Allow adequate recovery between max efforts
Using Your 1RM
| % of 1RM | Purpose |
|---|---|
| 50-60% | Speed/Power |
| 65-75% | Hypertrophy |
| 80-90% | Strength |
| 90-100% | Max Strength |