Estimate your one-rep max from any set, and get the working weights for every training percentage.
How strength is worked out
A one-rep max is the standard reference for programming strength work, but testing it is fatiguing and carries risk. Estimating from a submaximal set of three to eight reps is accurate enough for programming and far safer.
The percentage table below the result gives you the working weights most strength programmes are written around.
Using the calculator
- Enter the weight you lifted.
- Enter how many reps you completed.
- Read the estimated max and the percentage table.
The maths behind it
Epley: 1RM = weight × (1 + reps ÷ 30)
The default scenario, worked through
On the values this calculator opens with, the estimated 1RM is 116.7. Alongside it, Brzycki est. comes out at 112.5. Change any field and every figure updates as you type.
Common questions
How accurate are 1RM estimates?
Good within roughly 5% for sets of three to eight reps. Accuracy falls away above about ten reps.
How often should I test?
Estimating from working sets every few weeks avoids the fatigue and injury risk of frequent true maximal attempts.