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Estimated 1RM
| Reps | % of 1RM | Weight |
|---|---|---|
| 1 | 100% | - |
| 2 | 97% | - |
| 3 | 94% | - |
| 4 | 92% | - |
| 5 | 89% | - |
| 6 | 86% | - |
| 8 | 81% | - |
| 10 | 75% | - |
| 12 | 67% | - |
Calculate your One Rep Max for strength training
| Reps | % of 1RM | Weight |
|---|---|---|
| 1 | 100% | - |
| 2 | 97% | - |
| 3 | 94% | - |
| 4 | 92% | - |
| 5 | 89% | - |
| 6 | 86% | - |
| 8 | 81% | - |
| 10 | 75% | - |
| 12 | 67% | - |
The calculator uses established strength formulas to estimate your one-rep max (1RM) based on weight lifted and reps performed. Popular formulas include Epley (weight × (1 + reps/30)), Brzycki (weight × 36/(37-reps)), Lombardi (weight × reps^0.1), and O'Conner (weight × (1 + reps/40)).
Knowing your one-rep max helps you program training intensity, track strength progress, and set appropriate working weights. It's the foundation for percentage-based training programs used by powerlifters and strength athletes.
Different rep ranges target different training goals: 1-3 reps at 90-100% for strength, 4-6 reps at 85-90% for power, 8-12 reps at 67-80% for hypertrophy, and 15+ reps at less than 67% for endurance.
Always warm up thoroughly before attempting heavy lifts. Use a spotter for bench press and squats. Don't test 1RM more than once every 4-6 weeks. Focus on form over weight - ego lifting leads to injuries.
A one rep max (1RM) is the maximum amount of weight you can lift for a single repetition with proper form on a given exercise. It is the gold standard for measuring absolute strength and is commonly used for exercises like the bench press, squat, and deadlift. Your 1RM serves as the basis for percentage-based training programs, allowing you to set precise working weights for different rep ranges and training goals.
To safely test your 1RM, warm up thoroughly with progressively heavier sets (for example, sets at 50%, 70%, 80%, and 90% of your estimated max). Rest 3-5 minutes between heavy attempts. Always use a competent spotter for exercises like bench press and squats. Maintain strict form throughout every attempt. Alternatively, you can estimate your 1RM without the risk of maximal lifting by performing a set of 3-5 reps to failure and using a calculator like this one. This submaximal method is safer and recommended for most lifters.
1RM formulas are most accurate when using data from sets of 10 reps or fewer. The Epley and Brzycki formulas are generally considered the most reliable, with accuracy within 5% for low-rep sets. Accuracy decreases as the number of reps increases beyond 10, because the formulas were developed using lower rep data. Individual factors like training experience, muscle fiber type, and exercise selection also affect accuracy. For best results, use a weight you can lift for 3-5 reps and average the results from multiple formulas.