ironroot

One Rep Max Calculator

Estimate your one rep max from a working set.

  • Private
  • No sign-up
  • Works in your browser

Best with 1–10 reps.

Estimated one rep max
115 kg

Training percentages

% of 1RMWeight~Reps
100%115 kg1
95%109 kg2
90%103 kg4
85%97 kg6
80%92 kg8
75%86 kg10
70%80 kg12
65%74 kg15

What is the One Rep Max Calculator?

Enter the weight you lifted and for how many reps to estimate your one rep max, using the Epley and Brzycki formulas. You also get a percentage table to plan your training weights.

How to use it

  1. 1Enter the weight you lifted.
  2. 2Enter how many reps you performed.
  3. 3Read your estimated 1RM and training percentages.

Common uses

  • Planning strength training weights
  • Tracking progress over time
  • Setting percentages for a programme
Please note: Estimates only. Always warm up and use a spotter when lifting near your maximum.

Frequently asked questions

How accurate is a 1RM estimate?

Formulas are most accurate for sets of around 1–10 reps. The more reps you do, the less precise the estimate becomes.