One Rep Max Calculator | Strength Level Calculator

Estimated Rep Max Table (table)
Reps	% of 1RM	Est. weight

Calculate to see estimated weights for 1, 2, 3, 4, 5, 6, 8, 10 and 12 reps.

What Is a One Rep Max (1RM)?

Your one-rep max (1RM) is the heaviest weight you can lift for a single repetition of an exercise with correct technique. An estimated 1RM predicts that number from a set of several reps — for example, 100 kg for 5 reps — using an equation, so you don’t have to lift a maximal weight to know roughly where it is.

Lifters use 1RM to express strength on a common scale, to track progress over time, and to set training weights as a percentage of their max. It is also the figure used to compare a lift with the strength standards and in our Strength Level Calculator.

Actual 1RM is a weight you have lifted for one rep. Enter 1 rep and the calculator uses it as entered.
Estimated 1RM is a prediction from a multi-rep set. It can differ from what you would actually lift.
Formulas have limits. They were built from specific groups and lifts, agree at low reps and diverge at higher reps.

The Five 1RM Formulas

Each formula takes the weight (w) and reps (r) of your set and returns an estimated 1RM. The calculator shows all five and averages them. For a single rep, the weight you lifted is used as your 1RM.

Epley

1RM = w × (1 + r ÷ 30)

Adds one-thirtieth of the weight for every rep performed. Simple and widely used; it rises steadily as reps increase.

Brzycki

1RM = w × 36 ÷ (37 − r)

Scales the weight by 36 ÷ (37 − reps). Gives results close to Epley at low reps and lower estimates as reps climb.

Lander

1RM = 100 × w ÷ (101.3 − 2.67123 × r)

A linear equation that assumes each extra rep represents a fixed drop in the percentage of your max you can lift.

Lombardi

1RM = w × r^0.10

Multiplies the weight by reps raised to the power of 0.10. It rises slowly, so it tends to give the lowest estimates at higher reps.

Mayhew et al.

1RM = 100 × w ÷ (52.2 + 41.9 × e^(−0.055 × r))

An exponential equation from a study of bench press performance in college students. It tends to give higher estimates than the others.

Sources

Epley, B. (1985). Poundage Chart. Boyd Epley Workout. Lincoln, NE: Body Enterprises.
Brzycki, M. (1993). Strength testing — predicting a one-rep max from reps-to-fatigue. Journal of Physical Education, Recreation & Dance, 64(1), 88–90.
Lander, J. (1985). Maximums based on reps. National Strength and Conditioning Association Journal, 6, 60–61.
Lombardi, V. P. (1989). Beginning Weight Training. Dubuque, IA: W. C. Brown.
Mayhew, J. L., Ball, T. E., Arnold, M. D., & Bowen, J. C. (1992). Relative muscular endurance performance as a predictor of bench press strength in college men and women. Journal of Applied Sport Science Research, 6(4), 200–206.

Which Formula Should You Use?

No formula is the most accurate for every lifter or exercise. The equations come from different studies and populations, so each fits some people and lifts better than others. At low reps they usually agree within a few percent; as reps increase, their estimates spread further apart.

The average of the five is a reasonable middle estimate. If you track progress over time, choosing one formula and sticking with it keeps your numbers comparable from one set to the next.

Worked Example

Example only

A lifter completes 100 kg for 5 reps. Illustrative figures, not a real person’s result.

Epley100 × (1 + 5 ÷ 30) = 116.7 kg
Brzycki100 × 36 ÷ (37 − 5) = 112.5 kg
Lander100 × 100 ÷ (101.3 − 2.67123 × 5) = 113.7 kg
Lombardi100 × 5^0.10 = 117.5 kg
Mayhew et al.100 × 100 ÷ (52.2 + 41.9 × e^(−0.055 × 5)) = 119 kg
Average115.9 kg (range 112.5–119 kg)

Limitations of 1RM Formulas

Estimates, not tests
Every formula predicts a max from a submaximal set. Your actual 1RM may be higher or lower.
Accuracy drops with reps
Estimates are most useful from sets of about 1–10 reps. Above that, the formulas spread further apart.
Exercise and person vary
Rep performance differs between lifts, and between people with different training backgrounds.
Effort matters
A set stopped well short of failure makes the estimate low; a set with loose technique can make it high.

For a single lift, the Squat Calculator, Bench Press Calculator and Deadlift Calculator apply the same approach. If you rate sets by effort, the RPE Calculator accounts for reps left in reserve. Learn more in our guide to one-rep max.

Guide
What Is One Rep Max (1RM)? How to Calculate Your 1RM
What a one-rep max is, how it is estimated and how it is used to plan training.
Guide
How to Calculate Your Strength Level: A Complete Guide
How strength levels compare a lift with bodyweight-based standards, step by step, with a worked example.
Reference
Strength Standards
Compare a one-rep max with reference levels for the squat, bench press, deadlift, overhead press and barbell row.

Frequently asked questions

What is 1RM?

1RM, or one-rep max, is the heaviest weight you can lift for a single repetition of an exercise with correct technique. It is a common way to express maximal strength for a specific lift.

How is estimated 1RM calculated?

An estimated 1RM is predicted from a set of more than one rep using an equation. This calculator uses five published equations — Epley, Brzycki, Lander, Lombardi and Mayhew et al. — shows each result, and reports their average.

Which 1RM formula should I use?

No single formula is the most accurate for everyone. They were developed on different groups and lifts, and they agree closely at low reps but diverge at higher reps. A practical approach is to use the average, or to pick one formula and use it consistently so your estimates are comparable over time.

Is estimated 1RM accurate?

It is an approximation. Estimates tend to be closest to a tested max when they come from a hard set of roughly 1–10 reps with consistent technique. The more reps in the set, the more room there is for error.

Can I calculate 1RM from 5 reps?

Yes. A hard set of 5 reps is a common input for 1RM estimation, and it sits within the range where the formulas agree reasonably well. Enter the weight and 5 reps to see each formula’s estimate.

What is the difference between actual and estimated 1RM?

An actual 1RM is a weight you have lifted for one rep. An estimated 1RM is a prediction from a set of several reps. If you enter one rep, the calculator treats the weight as your actual single rather than an estimate.

Do I need to test my 1RM?

No. Many lifters use an estimated 1RM to plan training instead of testing a true max. If you do test one, use proper safety equipment or a spotter and only attempt weights you can control with good technique.

How do I use the rep max table?

The table estimates how much you might lift for other rep counts, based on your average estimated 1RM. Treat the numbers as estimates and a starting point, and adjust based on how the weight actually moves.

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