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1 Rep Max Calculator

Estimates a one-rep max from a submaximal set. Enter weight and reps completed to see Epley and Brzycki 1RM estimates plus common training percentages. For planning only — not medical or coaching advice. Stop if form breaks down.

The load you completed. Must be greater than zero.

1–12 clean reps work best. Brzycki is not defined at 37 or more.

Labels the results. Switching units does not convert the number.

Estimated 1RM

Epley 1RM
262.5 lb
Brzycki 1RM
253.13 lb
Average
257.81 lb
Training loads (percent of the Epley and Brzycki average)
Percent of 1RMWeight
90%232.03 lb
85%219.14 lb
80%206.25 lb
75%193.36 lb
70%180.47 lb

For planning only — not medical or coaching advice. Stop if form breaks down.

Frequently asked questions

What is a 1 rep max?

The heaviest weight you can lift for one clean repetition on a given exercise.

Which formula does this use?

It shows Epley and Brzycki estimates. They diverge more at higher rep counts.

How accurate is a calculated 1RM?

Best with 1–10 clean reps. High-rep sets overestimate for many lifters.

What percentages are shown?

Common training loads such as 90%, 85%, 80%, and 75% of the estimated 1RM.

Is this medical advice?

No. Warm up, use a spotter on heavy lifts, and consult a professional if you have injuries.

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