Free tool
One rep max calculator
Put in a recent hard set and see what you could lift for a single, plus your rep maxes, training percentages and the plates to load for each.
Estimated one rep max
– kg
Enter the weight and reps from a recent set.
- Training max (90%)
- – kg
- Heaviest triple
- – kg
- Heaviest five
- – kg
Sets above 10 reps give a rougher estimate. A heavy set of 3–5 is more accurate.
Formula comparison
The same set run through four well-known formulas. Highlighted is the one used above.
| Formula | Estimated 1RM |
|---|
Rep maxes
Roughly the most you could lift for each number of reps, rounded to weights you can load.
| Reps | Weight | Plates each side |
|---|
Percentages of your 1RM
For programmes written in percentages. Bar is 20 kg.
| % | Weight | Plates each side |
|---|
How it works
Different lifts follow different rep-to-max curves, so we pick the formula that fits each lift best: Wathan for squats and deadlifts, Mayhew for bench press and Epley for overhead, log and axle presses and everything else. It's the same set-up our members' tracker uses, so your numbers match in the gym. You can choose a different formula from the list.
It's an estimate. It works best with a set of 3 to 5 reps taken close to failure with good form. Grinding out a true max is a skill of its own, so treat the number as a guide, not a target for today.
Plates
Plate breakdowns use what's on our racks: 20151052.51.25 kg on a 20 kg bar. Weights round to the nearest 2.5 kg (5 lb).
Train with your numbers
Members get every session of Wirral 5/3/1 worked out from their maxes: weights, plates and progress tracked from one cycle to the next.