One-rep max calculator
Estimate your one-rep max (1RM) from the weight you lifted and the reps you completed in one set.
High-rep sets give a rougher estimate.
Estimated 1RM
How the estimate works
A one-rep max is the heaviest weight you can lift once. For multiple reps, the calculator uses the Epley formula. For a single rep, it shows the weight you lifted.
1RM = weight × (1 + reps ÷ 30)
For example, 100 kg for 5 reps gives an estimated 1RM of 116.67 kg. Use a recent set where you could barely finish the last rep.