💪 One Rep Max Calculator
Estimate your max lift from any rep range
Written by Albert Mateos · Founder & Editor
Last reviewed: May 2, 2026
How it works
Estimate your one-rep max (1RM) for any lift using the Epley and Brzycki formulas. Enter the weight you lifted and how many reps you completed. Get your estimated 1RM plus a full percentage table (95% down to 50%) for programming your training. Works for bench press, squat, deadlift, and any other lift.
How to Use This Calculator
- Select the exercise you want to estimate (bench, squat, deadlift, etc.).
- Enter the weight you lifted.
- Enter the number of clean reps you completed.
- Choose a formula (Epley or Brzycki) or compare both.
- Use the estimated 1RM to program training percentages.
Example
Inputs: Bench press 100 kg for 5 clean reps.
Result: Estimated 1RM of 116 kg (Epley) or 112 kg (Brzycki).
What it means: Most lifting programs would use ~115 kg as your working 1RM for calculating percentages like 70% for volume work or 85% for heavy singles.
Tips
- Estimates are most accurate with 3-8 reps. Above 10 reps the calculation overestimates, and below 3 reps it underestimates.
- Only count clean reps with proper form. A grinding rep with broken technique shouldn't be included.
- Test a true 1RM no more than every 12-16 weeks. Use calculated estimates for day-to-day programming.
- Actual 1RMs vary with sleep, stress, and fatigue. Expect your real max to land within 5% of the estimate on a good day.
- Brzycki is more conservative for low reps (1-5), while Epley fits higher reps (5-10) better. Average the two for a balanced estimate.
Frequently Asked Questions
- Which 1RM formula is most accurate?
- The Epley and Brzycki formulas are both accurate for reps under 10. For higher rep ranges (10+), accuracy decreases for all formulas. We show the average of both for the best estimate. For competition lifters, testing your actual 1RM is always more accurate.
- How should I use percentage-based training?
- Common programming uses: 50-65% for warm-ups, 70-80% for hypertrophy (8-12 reps), 80-90% for strength (3-6 reps), 90%+ for peaking (1-3 reps). Recalculate your 1RM every 4-8 weeks as you get stronger.
- Is it safe to test my actual 1RM?
- 1RM testing carries higher injury risk than submaximal training. Always warm up thoroughly, use a spotter, and only test when fully recovered. For most people, estimating from a 3-5 rep max is safer and nearly as accurate.
Authoritative resources
We recommend these external sources for further reading from recognized health organizations and peer-reviewed literature:
Scientific References
This calculator is based on peer-reviewed research and established health guidelines:
- Epley B. Poundage chart. Boyd Epley Workout Manual, University of Nebraska. 1985.
- Brzycki M. Strength testing — predicting a one-rep max from reps-to-fatigue. Journal of Physical Education, Recreation & Dance, 64(1): 88-90. 1993.