Free One Rep Max Calculator

Estimate your one-rep max (1RM) for any lift using the Brzycki formula based on weight and reps performed.

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lbs

Estimated 1RM

208.1 lbs

90% 1RM (2-3 reps)187.3 lbs
80% 1RM (7-8 reps)166.5 lbs
70% 1RM (12-15 reps)145.7 lbs

Estimated 1RM vs Weight Lifted

View formula & how it works →

Brzycki Formula

1RM = Weight x 36 / (37 - Reps)

The Brzycki formula is one of the most widely used 1RM estimation formulas. It is most accurate for sets of 1-10 reps.

Training Load Percentages

% of 1RMRepsTraining Focus 90-100%1-3Strength / Power 80-89%4-6Strength 70-79%8-12Hypertrophy 60-69%12-15Muscular endurance

Example Calculation

Bench pressing 185 lbs for 5 reps.

  1. 011RM = 185 x 36 / (37 - 5)
  2. 02= 185 x 36 / 32
  3. 03= 185 x 1.125 = 208.1 lbs
  4. 0490% = 187 lbs, 80% = 166 lbs, 70% = 146 lbs

Frequently Asked Questions

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