What is 1RM Calculator?
A bench press 1RM (One-Rep Max) calculator estimates the maximum weight you can lift for one repetition. This essential strength training tool helps athletes optimize workout intensity, track progress, and design effective training programs. By inputting your current weights and repetitions, our calculator uses scientific formulas to predict your max capacity while reducing injury risk from actual max attempts.
Calculate Your 1RM
1RM Calculation Formula
Our calculator uses the Epley Formula: 1RM = weight × (1 + reps/30). This scientifically validated equation provides accurate estimates for 1-10 repetitions. For higher rep ranges, we automatically switch to the Brzycki formula for improved accuracy.
How to Use
Enter the maximum weight you can lift for multiple reps (between 2-10 repetitions). Input both weight and repetitions into the calculator fields. Click calculate to instantly receive your estimated one-rep max. Use this value to set training weights at percentage-based intensities for optimal strength gains.
1RM Reference Table
| Reps | % of 1RM | Training Goal |
|---|---|---|
| 1 | 100% | Max Strength |
| 3 | 93% | Strength |
| 5 | 87% | Hypertrophy |
| 8 | 80% | Muscle Endurance |
| 10+ | 75% | Endurance |
Pros and Cons
Advantages:
- ✔️ Eliminates dangerous max attempts
- ✔️ Enables precise program design
- ✔️ Tracks strength progress objectively
- ✔️ Helps set appropriate training weights
- ✔️ Works for all experience levels
Limitations:
- ❌ Accuracy decreases above 10 reps
- ❌ Doesn't account for technique differences
- ❌ Variability between lifters (15% error possible)
- ❌ Doesn't consider fatigue or recovery state
- ❌ Should be validated with actual lifts periodically
FAQ
1. How accurate is the 1RM calculator?
The calculator provides 90-95% accuracy for 2-10 rep ranges using validated equations. Actual performance may vary based on individual factors like muscle fiber type and training experience.
2. Which formula is most accurate?
We use the Epley formula for best all-around accuracy. For advanced lifters, try different formulas and compare results for personal calibration.