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One-rep max calculator
Enter a set you actually did. Get your estimated max, and the loads to train at.
Your max moves. This page doesn't.
Antaeus re-estimates your 1RM from every set you log, then writes the next session's loads for you — and tells you when a lift has stalled and what to change.
Join the beta See how it worksQuestions
How accurate is a 1RM estimate?
Good within a few percent for sets of about 10 reps or fewer. Past that it reads high, because the Epley formula assumes a straight line that real fatigue does not follow.
Which formula does this use?
Epley: 1RM = weight × (1 + reps / 30). It is the same formula the Antaeus app uses, so the number here is the number you would see in the app.
Should I actually test my max?
Rarely. An estimate from a hard set of 3–5 is safer and nearly as useful. Test when you have a reason — a meet, or a programme that needs a true max.