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Strength estimate

1RM calculator

Enter the weight and reps you completed. The calculator gives an approximate one-rep max that can be used to compare workouts and track progress.

Calculate estimated 1RM

Estimated 1RM

The adjustment uses a reps-to-%1RM table: the strength profile estimates higher and the endurance profile lower. It is capped at ±5% and does not alter a single rep.

Estimates for 1–10 reps

Reps Weight % of 1RM
1
2
3
4
5
6
7
8
9
10

Weights are calculated backwards from the selected formula and profile. They are estimates, not guaranteed results.

This is an estimate, not a command to test a max single. Technique, fatigue and exercise choice still matter.

Why track 1RM

Estimated 1RM helps compare sets with different weights and reps. For example, 80×8 and 90×5 can be put on one scale.

It is useful when you want to understand whether the training load is really moving forward instead of only looking at the weight on the bar.

  • Use the same formula consistently.
  • Do not treat the number as a guaranteed real max.
  • Compare exercises only when their technique and range of motion are similar.

Why join us

The calculator gives you a quick estimate. In GYM Planner, estimated 1RM becomes part of your training log and helps you see progress over time:

  • Estimated 1RM is calculated automatically from completed sets for each exercise.
  • Compare sets with different weights and reps without recalculating them manually.
  • The history shows whether your estimated strength is actually growing from week to week.
Join GYM Planner