1RM calculator
Your one-rep max from any set, every rep max, and a percentage chart to load from.
Estimated 1RM
255lb
Rep maxes
| 1RM | 255 lb |
|---|---|
| 2RM | 245 lb |
| 3RM | 240 lb |
| 5RM | 225 lb |
| 8RM | 205 lb |
| 10RM | 195 lb |
Percentages of 255
| 50% | 130 lb |
|---|---|
| 55% | 140 lb |
| 60% | 155 lb |
| 65% | 165 lb |
| 70% | 180 lb |
| 75% | 190 lb |
| 80% | 205 lb |
| 85% | 215 lb |
| 90% | 230 lb |
| 95% | 240 lb |
| 100% | 255 lb |
How the estimate works
It uses the Epley formula: your weight × (1 + (reps − 1) ÷ 30). A true single counts as itself. Like every 1RM formula, it gets less reliable the more reps you did, so sets past 12 reps are counted as 12. The closer your set was to a true max effort, the better the estimate.
Rep maxes and percentages
Rep maxes run the same formula backwards: the weight you’d expect to move for 3 or 5 good reps. Percentages are of the estimated 1RM. Everything is rounded to a weight you can actually load: the nearest 5 lb, or 2.5 kg.
Using it for percentage work
Programmed at “5 × 3 @ 80%”? Find your 1RM here and read the 80% line. At a WodWiz gym, the app does this for you on every lift, from the numbers you’ve logged, so the weight is already next to each set when you log.
More free tools: Plate calculator · Erg pace calculator