Strength calculator
1 Rep Max Calculator
Estimate a clean one rep max from a working set, then turn it into usable training loads.
Use a hard set of 2-10 reps with clean form.
Estimated 1RM
Epley
262.5 lb
Brzycki
253.2 lb
Lombardi
264.3 lb
O'Conner
253.1 lb
Mayhew
267.8 lb
Wathan
262.3 lb
| Percent | Load | Reps | Purpose |
|---|---|---|---|
| 100% | 262.5 lb | 1 | Max strength |
| 95% | 250 lb | 2 | Max strength |
| 90% | 237.5 lb | 3-4 | Max strength |
| 85% | 222.5 lb | 5-6 | Strength |
| 80% | 210 lb | 7-8 | Strength |
| 75% | 197.5 lb | 9-10 | Hypertrophy |
| 70% | 185 lb | 11-12 | Hypertrophy |
| 65% | 170 lb | 13-15 | Technique or endurance |
| 60% | 157.5 lb | AMRAP | General work |
| 55% | 145 lb | AMRAP | General work |
| 50% | 132.5 lb | AMRAP | General work |
How the 1RM estimate works
The calculator runs Epley, Brzycki, Lombardi, O'Conner, Mayhew, and Wathan formulas. For most barbell lifts, sets of 2-8 reps are more useful than high-rep sets because fatigue and conditioning distort the estimate.
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Questions lifters ask
How accurate is a 1RM calculator? +
It is an estimate. Sets of 2-8 clean reps usually produce the most useful number. High-rep sets are less reliable because conditioning and technique fatigue distort the result.
Which 1RM formula should I use? +
Epley is a practical default for strength training. Brzycki often gives a slightly more conservative estimate. Comparing multiple formulas helps you avoid overreacting to one number.
Should I test a true max instead? +
Most lifters can train effectively from estimated maxes. Test true maxes only when you are healthy, practiced with heavy singles, and have a clear reason to do it.