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One Rep Max (1RM) Calculator

Estimate your max lift from a set you've done, and get the weights for every training percentage. Free, no sign-up, and it runs in your browser: nothing you type is sent anywhere.

Units
Estimated one-rep max
116.7 kg
Epley formula
Brzycki formula
112.5 kg
Average of both
114.6 kg
% of 1RMWeightReps possible
100%116.7 kg1
95%110.8 kg2
90%105.0 kg4
85%99.2 kg6
80%93.3 kg8
75%87.5 kg10
70%81.7 kg12
65%75.8 kg15
60%70.0 kg20
55%64.2 kg24
50%58.3 kg30

Use the table to pick training weights: strength around 85%+, muscle growth 65–85%. Always warm up and use a spotter for heavy lifts.

Read the full guide: How to Calculate Your One Rep Max (1RM) Safely

How to estimate your 1RM

Quick answer: To estimate your 1RM, do a hard set, enter the weight and reps and use the table.

  1. Do a hard set. Pick a weight you can lift 3–8 times with good form.
  2. Enter the weight and reps. Fewer reps give a more accurate estimate.
  3. Use the table. For example, strength work at 80–90% and hypertrophy at 65–80%.

Why estimate instead of testing?

Testing a true one-rep max is tiring and risky without a spotter. An estimate from a submaximal set is safer and close enough to plan your training.

Frequently asked questions

Which formula does it use?

Epley: 1RM = weight × (1 + reps ÷ 30), with Brzycki shown for comparison.