One Rep Max Calculator
Estimate your one rep max using three proven formulas. See a percentage chart with recommended rep ranges for programming your training.
Quick Answer
The Epley formula is the most popular: 1RM = Weight x (1 + Reps / 30). For a 185 lb lift done for 5 reps, your estimated 1RM is about 216 lbs. Use 80-85% of 1RM for strength (5-6 reps), 65-80% for hypertrophy (8-12 reps).
Your Estimated 1RM
Training Load Chart
Based on your average 1RM of 214 lbs
| % of 1RM | Weight | Reps | Training Zone |
|---|---|---|---|
| 100% | 214 lbs | 1 | Max Effort |
| 95% | 203 lbs | 2 | Strength |
| 90% | 193 lbs | 3-4 | Strength |
| 85% | 182 lbs | 5-6 | Strength |
| 80% | 171 lbs | 7-8 | Hypertrophy |
| 75% | 161 lbs | 8-10 | Hypertrophy |
| 70% | 150 lbs | 10-12 | Hypertrophy |
| 65% | 139 lbs | 12-15 | Endurance |
| 60% | 128 lbs | 15-20 | Endurance |
| 50% | 107 lbs | 20+ | Warm-up |
About This Tool
The One Rep Max Calculator estimates the maximum weight you can lift for a single repetition based on a submaximal lift. It uses three well-established formulas: Epley, Brzycki, and Lombardi. The average of all three gives a reliable estimate for programming your training.
The Three Formulas
The Epley formula (1RM = W x (1 + R/30)) is the most commonly used and works well across rep ranges. The Brzycki formula (1RM = W x 36/(37-R)) is very accurate for low rep counts but diverges at higher reps. The Lombardi formula (1RM = W x R^0.1) uses a power function and tends to give slightly lower estimates. Averaging all three provides a more robust estimate.
How to Use the Percentage Chart
The percentage chart is your roadmap for programming training intensity. For pure strength, train at 85-95% of your 1RM for 2-6 reps with long rest periods (3-5 minutes). For muscle growth (hypertrophy), train at 65-80% for 8-12 reps with moderate rest (60-90 seconds). For endurance, use 50-65% for 15+ reps. Periodizing between these zones maximizes long-term progress.
Accuracy Tips
For the most accurate estimate, use a weight you can lift for 3-5 reps. Accuracy decreases with higher rep counts because fatigue becomes a bigger factor than pure strength. Always use strict form for the test set. If you used any form breakdown or assistance, the estimate will be inflated. Retest every 4-8 weeks to track progress.
Frequently Asked Questions
What is a one rep max (1RM)?
Which 1RM formula is most accurate?
How do I use 1RM percentages for training?
Should I actually attempt a 1RM lift?
How often should I recalculate my 1RM?
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