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About the One Rep Max Calculator
This calculator estimates your one-repetition maximum, the heaviest weight you can lift for one clean repetition. Feed it the weight you lifted and the reps you managed, and it returns an estimated 1RM for that exercise. You can then build training programs around percentages of that number.
Most one-rep max calculators rely on the Epley formula: 1RM = weight × (1 + reps / 30). Some also show the Brzycki formula as a second estimate. Both methods need only two inputs: the load on the bar and the number of reps you completed. Accuracy drops above about 10 reps, so use a set of 1 to 10 controlled reps as your input, and consider a qualified coach before handling very heavy loads.
- Enter the weight you lifted in your set.
- Enter the number of reps you completed.
- Read your estimated 1RM and set training loads from a percentage of it.