Calculator
One-Rep Max Calculator
Estimate the most you could lift for a single rep, without a risky max attempt. Enter a weight and how many reps you did, and get a full training-percentage table.
Your lift
Estimated 1RM
The most you could likely lift for a single rep.
An estimate (Epley formula), most accurate at 10 reps or fewer. Always warm up and lift safely.
Training percentage table
Use these loads to plan your sets, most strength programs prescribe weight as a percentage of your 1RM.
| % of 1RM | Weight | Approx reps |
|---|---|---|
| 100% | — | 1 |
| 95% | — | 2 |
| 90% | — | 4 |
| 85% | — | 6 |
| 80% | — | 8 |
| 75% | — | 10 |
| 70% | — | 12 |
| 65% | — | 16 |
| 60% | — | 20 |
How it works
This calculator uses the Epley formula, which estimates your one-rep max from a weight you lifted for multiple reps. Estimating from a submaximal set is safer than a true max attempt, which carries more injury risk. The estimate is most reliable for sets of around ten reps or fewer.
Frequently asked questions
What is a one-rep max (1RM)?
Your one-rep max is the most weight you can lift for a single repetition of an exercise. It is a common benchmark for strength and for setting training loads.
How is 1RM estimated?
This calculator uses the Epley formula, which estimates 1RM from a weight you lifted and the number of reps. It is most accurate for sets of around 10 reps or fewer.
Why use percentages of 1RM?
Many training programs prescribe loads as a percentage of your 1RM, for example 5 reps at 80 percent. The table here shows the weights for each percentage so you can plan your sets.
Is estimating safer than testing?
Often, yes. Estimating from a submaximal set avoids the injury risk of a true max attempt. Always warm up and use a spotter for heavy lifts. welanutria provides estimates only.
What is a 1RM percentage chart?
A 1RM percentage chart shows how much weight to lift at different percentages of your one-rep max, and roughly how many reps each percentage allows. For example, about 90 percent of your 1RM is usually a set of 3 to 4 reps, while 70 percent is around 12. This calculator generates a full percentage chart from your estimated 1RM.
How do I calculate my one-rep max?
Enter the weight you lifted and the number of reps you completed. This calculator uses the Epley formula to estimate your one-rep max, then shows a percentage chart so you can plan your training loads without attempting a risky true max.
How many reps at each percentage of 1RM?
As a rough guide: 100 percent is 1 rep, 95 percent about 2, 90 percent about 4, 85 percent about 6, 80 percent about 8, 75 percent about 10, and 70 percent about 12 reps. The exact numbers vary by person and lift, but the chart above gives a solid starting point.
welanutria provides estimates for general information only and is not medical or fitness-coaching advice.