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One Rep Max Calculator

Estimate your one rep max from a lighter set, and get a training table from 50% to 95%.

Results

FormulaEstimated 1RM

Training loads

% of 1RMLoad
This is an estimate. Accuracy varies by exercise and experience, and it falls at higher reps. Do not test a true maximum without a spotter and proper technique. Speak to a doctor if you are new to strength training or have an injury.

Quick Answer

Your one rep max (1RM) is the most you could lift for one rep. The Epley formula estimates it as weight × (1 + reps ÷ 30), and Brzycki as weight × 36 ÷ (37 − reps). If you lift 225 lb for 5 reps, Epley gives 262.5 lb, Brzycki gives 253.1 lb, and the average is 257.8 lb.

Last updated: 2 November 2026 ·How we calculate this: Epley and Brzycki formulas

Table of Contents

How This One Rep Max Calculator Works

A one rep max is the heaviest weight you can lift once with good form. Testing it directly can be risky, so this calculator estimates it from a lighter set. It shows two widely used formulas side by side, along with their average.

Quick explanation: enter the weight and the reps you completed. The fewer reps, the more reliable the estimate.

  • Weight: the load you lifted.
  • Reps: completed with good form, from 1 to 12.
  • Training table: loads from 50% to 95% of your estimate.

How to Use the One Rep Max Calculator

  1. Warm up, then lift a weight you can move for about 2 to 6 good reps.
  2. Enter the weight and choose pounds or kilograms.
  3. Enter the number of reps you completed with good form.
  4. Press Calculate to see the Epley, Brzycki and average estimates.
  5. Use the training table to pick loads for your sets.

Core Formulas

  • Epley: 1RM = weight × (1 + reps ÷ 30)
  • Brzycki: 1RM = weight × 36 ÷ (37 − reps)
  • Average: (Epley + Brzycki) ÷ 2

The two formulas match at 10 reps. Below that, Epley gives a higher number. For a single rep, this calculator uses the weight lifted as the Epley result.

Worked Example

You lift 100 kg for 10 reps.

  • Epley = 100 × (1 + 10 ÷ 30) = 133.3 kg
  • Brzycki = 100 × 36 ÷ 27 = 133.3 kg
  • 80% training load = about 106.7 kg

Real-Life Examples

  • Planning a strength block: with an estimated 1RM of 257.8 lb, sets at 80% use about 206.2 lb.
  • Tracking progress safely: retest every few weeks with the same lift and rep range, without maxing out. If 185 lb for 5 reps becomes 195 lb for 5, your average estimate rises from about 212.0 lb to 223.4 lb.
  • Choosing a weight for a rep target: to find a weight for 8 reps, divide your 1RM by (1 + 8 ÷ 30). For a 300 lb 1RM, that is about 236.8 lb.

Epley vs Brzycki Formula

  • Epley: weight × (1 + reps ÷ 30). It gives higher estimates at low reps.
  • Brzycki: weight × 36 ÷ (37 − reps). It is often used for sets of 10 reps or fewer.
  • Same at 10 reps: both formulas give the same answer at exactly 10 reps.
  • Which to use: the average is a sensible middle ground, and using the same method each time matters most for tracking progress.

Reps at Each Percentage of 1RM

Rough guide to how many reps you may manage at each load, based on the Epley formula. Single reps are 100% by definition.

Reps% of 1RM (Epley)
1100%
294%
391%
488%
586%
683%
781%
879%
977%
1075%
1173%
1271%

Why Your Result May Differ

  • Exercise: studies found accuracy changes between lifts.
  • Experience: estimates can be less accurate for beginners.
  • Reps: sets of about 2 to 6 reps usually give a closer estimate than long sets.
  • Fatigue: use a set done when you are fresh, with good form.

Common Mistakes to Avoid

  • Using a set done to failure with poor form. Only count clean reps.
  • Using very high reps. Estimates from sets above 10 reps are less reliable.
  • Comparing different lifts. A bench press 1RM does not tell you your squat.
  • Training at 100% too often. Most sets in a program use lighter loads.
  • Testing a true max without a spotter. Use safety bars or a trained spotter.

Frequently Asked Questions

Lift a weight for several good reps, then enter the weight and reps here. A common formula is weight × (1 + reps ÷ 30).

No formula is best for everyone. Accuracy depends on the lift and the lifter, so this calculator shows two formulas and their average.

It depends on your goal and experience. Use the training table as a guide, and follow a program suited to you.

Beginners are usually safer estimating it from a lighter set. Get advice from a qualified coach before lifting near your maximum.

Estimates become less reliable as reps increase, so this calculator stops at 12.

Many lifters estimate it every 4 to 8 weeks. Using a lighter set and this calculator is safer than testing a true max often.

It works best for big lifts such as squat, bench press and deadlift. Accuracy can be lower for small or machine exercises.

It depends on body weight, age, sex and training history. Compare your estimate with your own past results to track progress.

References & Sources

SourceUsed ForLink
Validity of predictive equations for 1RM (University of the Sunshine Coast record) How accuracy changes by exercise. https://research.usc.edu.au/esploro/outputs/journalArticle/Validade-das-equações-preditivas-de-uma/99448976802621
Wikipedia, One-repetition maximum Epley and Brzycki formulas. https://en.wikipedia.org/wiki/One-repetition_maximum