What is a one-rep max?
A one-rep max (1RM) is the greatest weight you can lift for one repetition of an exercise with good form.
Strength calculator
One Rep Max Calculator
Estimate your one-rep max and useful training weights in seconds.
Estimated 1RM
Based on 185 lb × 5 reps
Epley estimate: weight × (1 + reps ÷ 30)
1RM estimates become less reliable above 20 reps.
Enter a weight and reps.Your estimate will appear here.
Training percentages
Use your estimate to choose a practical training load.
| % of 1RM | Weight | Typical reps |
|---|
Rep ranges are general training references, not guarantees or a prescribed program. Round to a load your equipment can actually make.
Training intensity
A quick way to read the percentage table.
Light50–65%
Moderate70–80%
Heavy85–90%
Very heavy95–100%
Estimated rep maxes
Approximate top weights for other rep targets, using the same Epley relationship.
How accurate is the estimate?
It works best with lower-rep sets. Fatigue, tempo, exercise choice, and individual response can change the result, so treat it as a useful estimate rather than an exact measurement.
Where can I use it?
Use it for bench press, squat, deadlift, overhead press, barbell rows, and other strength exercises. Make a separate estimate for each movement.
Straight answers
One-rep max questions
What does 1RM mean?
1RM means one-rep max: the greatest weight you can lift for one repetition of an exercise with good form.
How is one-rep max calculated?
This calculator uses the Epley formula: weight multiplied by one plus reps divided by 30. If you enter one rep, the result is the weight you entered.
How accurate is a 1RM calculator?
It is an estimate and generally works best with lower-rep sets performed with consistent technique. It cannot account for fatigue, tempo, exercise differences, or your individual strength profile.
Can I calculate 1RM from 5 reps?
Yes. A challenging five-rep set is a common way to estimate your 1RM without attempting a true maximum.
Should beginners test their true 1RM?
Beginners usually do not need to attempt a true maximum. A controlled multi-rep set and an estimate can be a more practical starting point while technique develops.
Does this work for bench press, squat, and deadlift?
Yes. It also works for overhead press, barbell rows, and other strength movements, although the estimate can be more or less accurate depending on the exercise.