One Rep Max (1RM) Calculator: Estimate Your Maximum Lift
If you can bench press 185 lbs for 5 reps, your estimated 1RM is approximately 216 lbs (Epley formula) or 208 lbs (Brzycki formula). Training percentages based on Epley: 80% (173 lbs) for 8 reps, 85% (184 lbs) for 5 reps, 90% (194 lbs) for 3 reps, 95% (205 lbs) for 1-2 reps.
Estimate Your 1 Rep Max
One rep-max strength calculator using Epley and Brzycki formulas.
Estimated 1RM
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Percentage Chart
| %1RM | Weight | Reps |
|---|
1RM Estimation Formulas
| Formula | Equation | Best For | ||||
|---|---|---|---|---|---|---|
| Epley (1985) | 1RM = weight x (1 + reps/30) | Most popular, good for 1-10 reps | ||||
| Brzycki (1993) | 1RM = weight x (36 / (37 - reps)) | Very similar to Epley, slightly conservative | ||||
| Lombardi (1989) | 1RM = weight x reps^0.10 | Better for higher rep ranges (10+) | Training Percentage Chart | % of 1RM | Reps (typical) | Training Effect |
| 100% | 1 | Max strength (testing) | ||||
| 95% | 2 | Peaking, competition prep | ||||
| 90% | 3 | Strength | ||||
| 85% | 5 | Strength-hypertrophy | ||||
| 80% | 8 | Hypertrophy-strength | ||||
| 75% | 10 | Hypertrophy | ||||
| 70% | 12 | Hypertrophy-endurance | ||||
| 65% | 15 | Muscular endurance | ||||
| 60% | 20 | Endurance, warm-up |
Accuracy Notes
These formulas are most accurate for 1-10 reps. Accuracy decreases beyond 10 reps because the relationship between weight and reps becomes less linear. For best results, use a weight you can lift for 3-7 reps with good form. The calculator averages all three formulas for a more reliable estimate.
Sources
Frequently Asked Questions
What is a one rep max?
Your one rep max (1RM) is the heaviest weight you can lift for a single complete repetition with proper form. It is the standard measure of maximal strength and the basis for percentage-based training programs. Most intermediate and advanced lifters program their training as percentages of their 1RM (e.g., 5x5 at 80% 1RM).
How accurate are 1RM calculators?
1RM calculators are most accurate within the 1-7 rep range, typically within 5% of your true 1RM. Accuracy decreases with higher reps because fatigue becomes a larger factor. The Epley and Brzycki formulas agree closely for low reps. For best accuracy, enter a weight you can lift for 3-5 reps with good form (not to failure with form breakdown).
Should I actually test my 1RM?
For most recreational lifters, estimating 1RM from submaximal sets is safer and sufficient. True 1RM testing should be done with a spotter, proper warm-up (progressive sets building to max), and good form. Beginners and those with less than 6 months of training should avoid true 1RM testing. Experienced lifters typically test every 8-12 weeks at the end of a training cycle.
How do I use my 1RM for training?
Most strength programs prescribe weights as percentages of 1RM. Example: a 5x5 program at 80% means 5 sets of 5 reps at 80% of your max. If your squat 1RM is 300 lbs, you would squat 240 lbs for 5x5. Popular programs like Starting Strength, 5/3/1, and Juggernaut Method all use 1RM percentages for programming.
What is a good one rep max for bench press?
Standards vary by body weight and training experience. General benchmarks for men: beginner (0.5x body weight), intermediate (1x body weight), advanced (1.5x body weight), elite (2x body weight). For women: beginner (0.25x), intermediate (0.75x), advanced (1x), elite (1.5x). These are approximate and vary by federation and body weight class.