Free tool

Calculate your 1RM

Enter the weight you lifted and how many reps you did. You'll get your estimated one rep max plus training percentages for every goal.

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kg estimated 1RM

Training percentages

GoalWeightReps

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How does the 1RM calculation work?

Your 1RM (one repetition maximum) is the most weight you can lift for a single rep. Rather than actually testing that -- which carries real injury risk -- we use the Epley formula: 1RM = weight x (1 + reps / 30). It's the most widely used formula in sports science.

The estimate is most accurate between 3 and 8 reps. Above 10 reps it gets less reliable. For most training programs you'll be working between 60-85% of your 1RM, depending on your goal.

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