One Rep Max Calculator: 1RM + Training Weights

Estimate your one-rep max (1RM) safely from a set of 2–10 reps, without grinding out a true max. Enter the weight and reps to get your estimated 1RM, a training-weight table from 50% to 95%, and rough strength benchmarks for the squat, bench, deadlift and overhead press.

Use a set of 12 reps or fewer. 3–6 reps gives the best estimate.

Optional. Used only to compare your lift with body-weight benchmarks.

Estimated one-rep max
0 kg
0Epley formula
0Brzycki formula
0reps entered

Training weights from your 1RM

% of 1RM Weight Max reps (approx.) Typical use
“Max reps” is roughly how many reps most people can do at that load before failing. In normal training, stop 1–3 reps short of that. Everyone is different, so adjust if a weight feels much easier or harder than the table suggests.

Rough strength benchmarks (men)

Lift Beginner Intermediate Advanced
Testing your max after 35: you rarely need a true 1RM to train well, and an estimate from a set of 3–6 good reps is enough to plan your weights. If you do test, warm up gradually, use safety bars or a spotter, keep breathing (no long breath-holds), and stop the moment your form breaks. Check with your doctor first if you have a heart condition, high blood pressure, a recent injury or take heart or blood-pressure medication. Stop and get checked if you feel chest pain or pressure, dizziness, palpitations or unusual breathlessness.

How this one-rep max calculator works

The calculator uses two of the most widely used prediction equations and shows their average. The Epley formula is 1RM = weight × (1 + reps ÷ 30). The Brzycki formula is 1RM = weight × 36 ÷ (37 − reps). For a single rep, your 1RM is simply the weight you lifted. Both formulas agree closely at low reps and drift apart as reps go up, which is why the tool stops at 12 reps: research comparing these equations found predictions are more accurate when you use fewer than 10 reps.

The training-weight table uses the percentage-to-reps chart published by the National Strength and Conditioning Association (for example about 87% for 5 reps, 75% for 10 and 70% for 12). The “typical use” column follows the NSCA’s guide to loads (roughly 85% or more for strength, 67–85% for muscle growth, 67% or less for muscular endurance) and the ACSM position stand, which suggests light to moderate loads of 40–60% of 1RM for high-rep endurance work. ACSM also advises beginners to start with loads they can lift 8–12 times.

About the strength benchmarks

The beginner, intermediate and advanced numbers are common coaching benchmarks, not research standards. They are round body-weight multiples that coaches often use as rough milestones for men, such as a body-weight bench press or a double body-weight deadlift. For a reality check, crowd-sourced data from Strength Level (millions of lifts logged by its users) puts the typical “intermediate” 80 kg man at about 132 kg squat, 98 kg bench, 155 kg deadlift and 62 kg overhead press, or roughly 1.65×, 1.2×, 1.95× and 0.8× body weight. People who log lifts in an app are keener than average, so treat any benchmark as a loose guide. Women’s benchmarks are lower, and your best comparison is always your own progress over time.

Want to build these numbers steadily? Read Strength training after 35, the beginner-friendly Start working out after 40 guide, and how much protein you need to support your training.

Sources

  1. Epley B. (1985). Poundage chart. Boyd Epley Workout. Lincoln, NE: Body Enterprises (origin of the Epley equation).
  2. Brzycki M. (1993). Strength testing: predicting a one-rep max from reps-to-fatigue. Journal of Physical Education, Recreation and Dance 64(1):88–90
  3. Mayhew et al. (2008), Journal of Strength and Conditioning Research: accuracy of 1RM prediction equations (better with fewer than 10 reps)
  4. National Strength and Conditioning Association: training load chart (% of 1RM vs reps)
  5. American College of Sports Medicine (2009) position stand: progression models in resistance training for healthy adults
  6. Paluch et al. (2024), Circulation: resistance exercise training in people with and without cardiovascular disease, AHA 2023 update
  7. Strength Level: crowd-sourced male strength standards (user data, not a research standard)

This calculator gives general education, not medical advice. Estimates vary between people and exercises. Check with your doctor before heavy lifting if you have a heart condition, high blood pressure, an injury or another health condition.

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