One rep max calculator (1RM) with percentage chart
Type the weight and the reps of a hard set. You get an estimated one rep max and what that strength works out to for 1 to 12 reps, with no account and no email.
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What that means
How the estimate works
The estimate is the Epley formula: 1RM = weight × (1 + reps ÷ 30). It is applied to every rep count, including a single, so a one-rep set estimates a max a little above the weight on the bar.
The chart runs the same formula backwards: the weight for a number of reps is 1RM ÷ (1 + reps ÷ 30). That is why the estimate and the chart always agree with each other.
The calculator stops at 12 reps. Prediction equations drift further from a tested max as the reps go up, and how many reps a person can do at a given percentage varies a lot between people and between lifts.
Brzycki's formula, 1RM = weight × 36 ÷ (37 - reps), is the other common one. It gives a lower estimate than Epley below 10 reps, the same estimate at 10, and a higher one above 10. The comparison table below shows both for the same set.
Sources
- Epley B. Poundage chart. Boyd Epley Workout, Lincoln, Nebraska, 1985.
- Brzycki M. Strength testing: predicting a one-rep max from reps-to-fatigue. Journal of Physical Education, Recreation & Dance. 1993;64(1):88-90.
- LeSuer DA, McCormick JH, Mayhew JL, Wasserstein RL, Arnold MD. The accuracy of prediction equations for estimating 1-RM performance in the bench press, squat, and deadlift. Journal of Strength and Conditioning Research. 1997;11(4):211-213.
A worked example
A set of 225 lb for 5 reps: 225 × (1 + 5 ÷ 30) = 262.5, so the estimated max is about 263 lb.
At that strength, 8 reps works out to about 207 lb and 3 reps to about 239 lb. Brzycki's formula puts the same set at about 253 lb.
Reference tables
| Reps | % of 1RM |
|---|---|
| 1 | 97% |
| 2 | 94% |
| 3 | 91% |
| 4 | 88% |
| 5 | 86% |
| 6 | 83% |
| 7 | 81% |
| 8 | 79% |
| 9 | 77% |
| 10 | 75% |
| 11 | 73% |
| 12 | 71% |
| Reps | 135 lb max | 185 lb max | 225 lb max | 275 lb max | 315 lb max | 405 lb max |
|---|---|---|---|---|---|---|
| 1 rep | 131 | 179 | 218 | 266 | 305 | 392 |
| 3 reps | 123 | 168 | 205 | 250 | 286 | 368 |
| 5 reps | 116 | 159 | 193 | 236 | 270 | 347 |
| 8 reps | 107 | 146 | 178 | 217 | 249 | 320 |
| 10 reps | 101 | 139 | 169 | 206 | 236 | 304 |
| 12 reps | 96 | 132 | 161 | 196 | 225 | 289 |
| Reps | 60 kg max | 80 kg max | 100 kg max | 120 kg max | 140 kg max | 180 kg max |
|---|---|---|---|---|---|---|
| 1 rep | 58 | 77 | 97 | 116 | 135 | 174 |
| 3 reps | 55 | 73 | 91 | 109 | 127 | 164 |
| 5 reps | 51 | 69 | 86 | 103 | 120 | 154 |
| 8 reps | 47 | 63 | 79 | 95 | 111 | 142 |
| 10 reps | 45 | 60 | 75 | 90 | 105 | 135 |
| 12 reps | 43 | 57 | 71 | 86 | 100 | 129 |
| Reps | Epley | Brzycki |
|---|---|---|
| 1 | 233 lb | 225 lb |
| 2 | 240 lb | 231 lb |
| 3 | 248 lb | 238 lb |
| 4 | 255 lb | 245 lb |
| 5 | 263 lb | 253 lb |
| 6 | 270 lb | 261 lb |
| 8 | 285 lb | 279 lb |
| 10 | 300 lb | 300 lb |
| 12 | 315 lb | 324 lb |
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- How do I calculate my one rep max?
- Multiply the weight by 1 plus the reps divided by 30. 225 lb for 5 reps gives 225 × (1 + 5 ÷ 30) = 262.5 lb. That is the Epley formula, which this calculator uses.
- How accurate is a one rep max calculator?
- It is an estimate, not a tested max. Sets with fewer reps tend to predict a tested max more closely, which is why this calculator only takes sets of 1 to 12 reps. Use the number to choose training weights.
- What percentage of my 1RM should I lift for 8 reps?
- About 79% by the Epley formula. The percentage table on this page lists every rep count from 1 to 12.
- Should I use Epley or Brzycki?
- They agree at 10 reps. Below 10, Brzycki estimates a little lower, and above 10 a little higher. This calculator uses Epley, the same formula the CoachVana app uses for the estimated max on a logged set.
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