Calculate Your One-Rep Max
Estimate the maximum weight you could lift for one repetition. Calculate your strength percentages for bench press, squat, deadlift, overhead press, and other resistance exercises.
Calculate Your Estimated 1RM
Enter a recent working set performed with good technique. Your result is an estimate, not a guaranteed maximum.
Rounding applies only to training weights, not your estimated 1RM. Choose increments that match your available equipment.
Training Weights by Percentage
Use these figures as starting points for programming. Actual repetitions possible vary by exercise, technique, and individual. Rounded weights are approximate.
| 1RM percentage | Suggested use | Calculated weight |
|---|
What Is a One-Rep Max?
Your one-repetition maximum (1RM) is the heaviest weight you can lift for one complete repetition using the intended range of motion and acceptable technique. It is commonly used to assess strength and prescribe resistance-training loads.
You can estimate your 1RM without attempting a true maximum lift. Enter the weight you lifted and the number of repetitions you completed into the calculator above to get an estimated result.
How to Use the 1RM Calculator
- Choose an exercise. Use a recent set from the lift you want to estimate, such as the squat, bench press, or deadlift.
- Enter the weight. Include the total weight lifted, using kilograms or pounds.
- Enter your repetitions. Select how many complete reps you performed with that weight.
- Select a formula. Epley is a common general-purpose estimate. Brzycki and Lombardi provide alternative estimates.
- Calculate your result. Review the estimated 1RM and the suggested percentages to plan your training loads.
1RM Formulas Explained
Different equations estimate your maximum from a submaximal set. They may produce different results for the same weight and repetitions because each formula models the relationship between reps and maximum strength differently.
1. Epley Formula
Estimated 1RM = weight × (1 + repetitions ÷ 30)
Epley is a widely used, straightforward estimate. For example, lifting 80 kg for 5 repetitions gives an estimated 1RM of about 93.3 kg.
2. Brzycki Formula
Estimated 1RM = weight × 36 ÷ (37 − repetitions)
This is another common equation for estimating a maximum from a submaximal set. Its predictions can differ from those of Epley, particularly as repetitions increase.
3. Lombardi Formula
Estimated 1RM = weight × repetitions0.10
Lombardi uses a power-based equation and offers a third estimate for comparison. No formula is perfectly accurate for every person or exercise.
How to Use Your 1RM to Choose Training Weights
Many strength programs prescribe loads as a percentage of your estimated 1RM. A higher percentage generally represents a heavier load, while lower percentages can be useful for technique practice, volume, or lighter training sessions.
| Percentage | General application |
|---|---|
| 90–100% | Very heavy loads; typically low repetitions |
| 80–89% | Heavy strength-focused work |
| 70–79% | Moderate-heavy strength and muscle-building work |
| 60–69% | Moderate loads, often suited to higher-repetition sets |
| Below 60% | Lighter work, technique practice, or specific programming needs |
These are broad guidelines rather than fixed rules. Your program, training experience, exercise selection, and proximity to failure all influence the appropriate load. Do not assume a percentage always corresponds to a specific number of repetitions.
Once you have estimated your one-rep max, you can use it to choose training loads for structured strength workouts. Explore our powerlifting workout programs to put percentage-based training into practice.
Estimated 1RM vs. a True 1RM
An estimated 1RM predicts your maximum from a set of multiple repetitions. A true 1RM is the heaviest load you successfully lift for one repetition under the conditions being tested.
Estimation is useful for routine programming because it avoids the need to test a maximal lift frequently. However, results depend on your technique, fatigue, training experience, exercise, and the quality of the set used for the calculation.
Frequently Asked Questions
Is a 1RM calculator accurate?
It provides an estimate, not a guaranteed maximum. Accuracy varies by individual, exercise, formula, and repetitions completed. Estimates are generally more useful when based on a challenging set of relatively few repetitions performed with consistent technique.
Can I calculate my bench press, squat, and deadlift 1RM?
Yes. Enter a set from the specific exercise you want to estimate. Calculate each lift separately because performance and repetition ability differ between exercises.
Which 1RM formula should I use?
Epley is a practical starting point for many lifters. You can compare it with Brzycki or Lombardi, but avoid treating the highest result as automatically correct. Consistent testing conditions matter more than choosing one supposedly perfect formula.
Should beginners test their true one-rep max?
Beginners generally do not need to attempt maximal lifts to build strength. Use manageable loads, focus on technique, and consider a qualified coach’s guidance before attempting heavy testing. For a structured starting point, see our 3-day beginner gym workout plan.
How often should I recalculate my 1RM?
You can recalculate it when your working weights or repetitions improve, or periodically during a training block. Use comparable exercises, technique, and effort levels to make progress comparisons more meaningful.
References and Further Reading
The following scientific publications provide background on one-repetition maximum (1RM) estimation, strength testing, and resistance-training recommendations.
- Reynolds, J. M., Gordon, T. J., & Robergs, R. A. (2006). Prediction of one repetition maximum strength from multiple repetition maximum testing and anthropometry. Journal of Strength and Conditioning Research, 20(3), 584–592. View Study
- American College of Sports Medicine. (2009). Progression models in resistance training for healthy adults. Medicine & Science in Sports & Exercise, 41(3), 687–708. View Guidelines
- American College of Sports Medicine. (2026). Resistance training prescription for muscle function, hypertrophy, and physical performance in healthy adults: An overview of reviews. Medicine & Science in Sports & Exercise. View Updated Guidelines