1RM calculator: estimate your one-rep max
Your 1RM (one-rep max) is the heaviest weight you can lift once with good form. You don’t have to test it. Enter the weight and the reps of one hard set and the calculator estimates the rest.
Please enter a weight above 0 and 1 to 12 reps.
Estimated 1RM
Your weight for 1 to 12 reps
| Reps | Weight (kg) | Share of 1RM |
|---|
How it is calculated
We use the Epley formula: 1RM = weight × (1 + reps ÷ 30). For one rep, the 1RM is the weight itself.
Example: 80 kg × 8 reps gives 80 × (1 + 8 ÷ 30) = 101.3 kg.
Good to know
- The more reps you enter, the less accurate the estimate. It usually fits best at 3 to 8 reps.
- Your daily form, technique and fatigue change the result. It is an estimate, not a measurement.
- If you want to test your true max, do it with a spotter and after a good warm-up.
What you need it for
With your 1RM you can plan weights for a goal: heavier sets with few reps for strength, moderate weights with more reps for muscle building. Which ranges fit which goal is on the page Reps for strength or muscle?.
Keep track of your sets
In fbe you log every set and see your history. That way you can tell whether weight or reps go up from week to week.
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