Epley
Proposed by Boyd Epley in 1985.
- Formula
- 1RM = weight × (1 + reps / 30)
- When it’s used
- Very common and simple. It tends to give the highest of the three at low reps.
- Keep in mind
- Beyond 10 reps the estimate gets less reliable.
1RM calculator: your one-rep max
Enter the weight and reps of your best set and see how much you could lift for a single rep, with the weights for each percentage.
Working out your max…
- Epley formula
- Brzycki formula
- Lombardi formula
- Percentage table
Your estimated 1RM
0kg
Epley
Brzycki
Lombardi
Weights by percentage
| % of 1RM | Weight | Approx. reps |
|---|
A rough estimate. To test a true max, warm up properly and have someone spot you.
What each formula is
All three estimate your max from a weight and the reps you managed. This calculator shows all three and uses the average.
Brzycki
Published by Matt Brzycki in 1993.
- Formula
- 1RM = weight × 36 / (37 − reps)
- When it’s used
- Widely used in strength training practice. It usually gives the most conservative value.
- Keep in mind
- It climbs very fast as reps approach 37, which is why this calculator stops at 12.
Lombardi
Proposed by Lombardi in 1989.
- Formula
- 1RM = weight × reps^0.10
- When it’s used
- A middle ground between the other two for low-rep sets.
- Keep in mind
- It’s less well known, so it may not match other websites when you compare.
Frequently asked questions
How do I work out my 1RM for bench press, squat or deadlift?
It works the same for all three: take the weight from a set taken to failure between 3 and 10 reps in that exercise, enter it with the reps and press Calculate. You can type the exercise name to remember it. Your 1RM is different for each exercise, so work them out separately.
What is 1RM?
It’s the maximum weight you can lift once with good technique in an exercise. It’s used to work out what weight to train with for the percentage you want to work at.
Which formula is the most accurate?
None is always the best: they’re all estimates and they land close to each other at low reps. That’s why the calculator shows all three and uses the average. Reliability drops beyond about 10 reps.
How many reps should I use?
The best input is a set of 3 to 10 reps taken to failure, meaning you couldn’t have done another one.
What are the percentages for?
To choose the weight for your sets. As a rough guide, the heaviest weights (around 85 % or more) are used for strength work at low reps, and the middle ones (65–80 %) for sets with more reps.
Is it safe to test my real 1RM?
If you want to find out for real, warm up well, add weight gradually and do it with a spotter or safety pins. Otherwise, the estimate from this calculator avoids the risk.