Toolstia / one-rep max calculator
One-rep max calculator
Enter the weight you lifted and how many reps you did. The calculator estimates your one-rep max with six common formulas and gives a table of training percentages.
Estimates are most accurate for sets of 10 reps or fewer. They assume the set was taken close to failure with good form. Never test a true one-rep max without a spotter and a proper warm-up.
How it works
- Enter the weight and the reps.
- Read the estimated 1RM.
- Use the percentage table to plan your sets.
Formulas
Epley, Brzycki, Lombardi, Mayhew, O’Conner and Wathan are shown, with their average.
Accuracy
Estimates are most accurate for sets of 10 reps or fewer.
Percentage table
Training plans often use percentages of 1RM, from 50 to 100 percent.
Safety
Never test a true one-rep max without a spotter and a warm-up.
Questions
Any unit?
Yes. Use kilograms or pounds and the answer is in the same unit.
Why do the formulas differ?
They were fitted to different groups and lifts.
Is my data stored?
Everything is worked out in your browser, and nothing you type is sent anywhere.