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One Rep Max Calculator (1RM)

Estimate your one rep max (1RM) without actually attempting a maximal lift. Enter the weight you lifted and how many reps you completed, and this calculator uses three proven formulas to predict your true 1RM and generate a complete percentage table for programming your training.

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1

Enter your details

kg

Use 2-10 reps for best accuracy

Your One Rep Max

Example

Example figures, not your own. Worked for 5 reps at 80 kg. Enter your own details and press Calculate.

Estimated 1RM (Average)

91kg

Epley

93kg

Brzycki

90kg

Lander

91kg

Training Load Table

Reps% of 1RMWeight (kg)
1100%91 kg
295%87 kg
393%85 kg
490%82 kg
587%80 kg
685%78 kg
783%76 kg
880%73 kg
977%70 kg
1075%69 kg
1173%67 kg
1270%64 kg

How It Works

Three formulas estimate your 1RM from a submaximal effort. Epley: 1RM = weight x (1 + reps/30). Brzycki: 1RM = weight x 36/(37 - reps). Lander: 1RM = 100 x weight / (101.3 - 2.67123 x reps). The calculator averages all three for a best estimate and generates a percentage table showing target weights from 100% (1RM) down to 65% (12RM) for training programming.

How to use it

  1. 1Enter the weight you lifted in kilograms
  2. 2Enter the number of reps completed (2-12 reps for best accuracy)
  3. 3Click "Calculate" to see your estimated 1RM from three formulas
  4. 4Use the percentage table to program your training sets

Quick Reference

Reps% of 1RMTraining ZonePrimary Benefit
1100%Max StrengthPeak force production
295%Max StrengthNeural strength gains
393%StrengthStrength with low fatigue
490%StrengthHeavy strength work
587%StrengthBalanced strength & volume
685%Strength-HypertrophyStrength with muscle growth
880%HypertrophyMuscle building
1075%HypertrophyVolume-based muscle growth
1270%Endurance-HypertrophyMuscular endurance

Percentages are approximate. Individual variation depends on training history, muscle fibre type, and exercise type.

One Rep Max Formulas

Epley: 1RM = W × (1 + R/30) Brzycki: 1RM = W × 36/(37 - R) Lander: 1RM = 100 × W / (101.3 - 2.67 × R)
W
= Weight lifted in kilograms
R
= Number of repetitions completed
1RM
= Estimated one repetition maximum

All three formulas are well-validated for 2-10 reps. Accuracy decreases significantly above 10 reps. The average of all three formulas provides the most reliable estimate.

Frequently Asked Questions

Which 1RM formula is the most accurate?
The Brzycki and Epley formulas are both well-validated and give very similar results for low rep ranges (2-6 reps). For higher rep ranges (8-12), accuracy decreases for all formulas. Using the average of multiple formulas provides the most reliable estimate.
How many reps should I use for the best estimate?
Use a set of 3-5 reps to failure for the most accurate 1RM prediction. Sets of 1-2 reps are too close to max and risky, while sets of 10+ reps introduce significant error. A solid 5RM test is the sweet spot for safety and accuracy.
How often should I test my 1RM?
Directly testing a true 1RM is taxing and carries injury risk. Most coaches recommend testing every 8-12 weeks, or simply using the calculator with a recent heavy set. Beginners should avoid true 1RM attempts entirely and rely on calculated estimates.
What is a good 1RM for bench press?
For an intermediate male lifter weighing 80 kg, a bench press 1RM of 80-100 kg (1x-1.25x bodyweight) is solid. For women at 65 kg, 40-55 kg is a good intermediate level. Strength standards vary significantly by training experience.

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