This calculator estimates a one-rep maximum for lifters who know the weight and repetitions from a recent hard set.
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Enter the lifted weight and the number of clean repetitions completed without assistance. Sets of about 2 to 10 repetitions usually give a more useful estimate than very high-repetition sets.
Using the Epley formula, estimated 1RM = weight × (1 + repetitions / 30). It is an estimate, since technique, fatigue, exercise choice, and training history all affect the result.
If you bench press 80 kg for 6 repetitions, estimated 1RM = 80 × (1 + 6 / 30). The result is 96 kg, so loading 96 kg without suitable safety equipment would be a fairly bold interpretation of a spreadsheet.
It is usually most useful for setting training percentages, not proving an exact maximum. Accuracy drops with high-repetition sets or exercises where technique changes under fatigue.
No. Many programs work well from an estimated maximum, which avoids the fatigue and added risk of frequent maximal attempts.
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