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.

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.

Enter Your Details

Weight Lifted

Reps Completed

Use 2-10 reps for best accuracy

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.

Quick Reference

Reps	% of 1RM	Training Zone	Primary Benefit
1	100%	Max Strength	Peak force production
2	95%	Max Strength	Neural strength gains
3	93%	Strength	Strength with low fatigue
4	90%	Strength	Heavy strength work
5	87%	Strength	Balanced strength & volume
6	85%	Strength-Hypertrophy	Strength with muscle growth
8	80%	Hypertrophy	Muscle building
10	75%	Hypertrophy	Volume-based muscle growth
12	70%	Endurance-Hypertrophy	Muscular endurance

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

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.

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.

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Disclaimer

This calculator provides estimates for informational purposes only and should not be considered medical advice. Individual results may vary based on factors not captured by these formulas. Consult a healthcare professional before making changes to your diet or exercise routine, especially if you have any existing health conditions.