general purpose
best for 10 reps or fewer
alternative method
—
Note: this is only an estimate. Do not force an actual 1RM attempt.
Comparison of the 3 formulas
Weight guide (% of 1RM)
Your 1RM (One-Rep Max) is the heaviest weight you can lift for a single repetition with good form. It is the reference point used to program training intensity for strength lifts such as the bench press and squat. Because attempting a true max is risky, this tool estimates your 1RM from a weight you can lift for several reps.
How to use this tool
Enter a weight you recently lifted close to failure, along with the number of reps you completed. For example, if you pressed 60 kg for 8 reps, enter 60 and 8. Estimates are most accurate at around 10 reps or fewer; above 15 reps the result reflects muscular endurance more than maximal strength, so accuracy drops.
Three formulas and reading the result
This tool shows three well-known estimation formulas side by side: Epley, Brzycki and Lander. A few kilograms of difference between them is normal, because each was derived from different data. Use the average as a guide and treat the result as a range. From your estimated 1RM you can set daily working weights as a percentage: roughly 67-85% for hypertrophy, 85%+ for strength, and below 67% for endurance.
Tips
Your 1RM changes with your condition, the exercise and your technique. Re-test about once a month under the same conditions and log the numbers to make progress visible. You can track all of your workouts in the Joy Next World Gym app.
What is 1RM (one-rep max)?+
For example, if you can just barely bench press 100kg for one rep, then your bench press 1RM is 100kg.
Because attempting an actual 1RM carries a risk of injury, a method that estimates it from multi-rep sets — like this tool — is widely used.
What is the difference between the Epley, Brzycki and Lander formulas?+
Epley:
1RM = weight × (1 + reps / 30)The most widely used general-purpose formula. It works well even with higher rep counts.
Brzycki:
1RM = weight × 36 / (37 − reps)Considered especially accurate for 10 reps or fewer.
Lander:
1RM = (100 × weight) / (101.3 − 2.67 × reps)An alternative calculation approach.
This tool displays the results of all three formulas side by side, so you can compare them for reference.
What % of 1RM should I train at?+
Muscle growth (getting bigger): 65–85% of 1RM (a weight you can do for 6–12 reps)
Strength (lifting heavier): 85–95% of 1RM (a weight you can do for 1–5 reps)
Muscular endurance (lasting longer): 50–65% of 1RM (a weight you can do for 15+ reps)
As a beginner, prioritize learning proper form first, and we recommend starting at around 60–70% of your 1RM.
The result seems off. Why?+
・Individual differences in muscle mass, bone structure and body type
・Your condition and fatigue level on the day
・Using too many reps (accuracy drops above 10 reps)
Accuracy is highest when reps are 10 or fewer. For a more accurate estimate, we recommend using a weight that brings you to failure at 6–8 reps.
・Epley (1985). Poundage chart. NSCA Journal, 6(6), 49.
・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. NSCA Journal, 6(6), 60–61.
The results of this tool are a guideline based on scientific estimation formulas and do not guarantee your actual maximal strength. Results vary by individual fitness, body type and condition. Training with weights above the estimated value carries a risk of injury. If you have any health concerns, please consult a doctor or trainer. This service is for informational purposes only and is not a substitute for medical or training advice.
Track Your Workouts in the App
Log weights, reps and menus — Joy Next World Gym App is free to use.