๐๏ธ One-Rep Max Calculator
| % | Weight |
|---|---|
| 100% | 93.3 kg |
| 95% | 88.7 kg |
| 90% | 84.0 kg |
| 85% | 79.3 kg |
| 80% | 74.7 kg |
| 75% | 70.0 kg |
| 70% | 65.3 kg |
| 65% | 60.7 kg |
| 60% | 56.0 kg |
| 50% | 46.7 kg |
Enter a weight you lifted and how many reps you performed, and this tool estimates your one-rep max (1RM) using the Epley formula. It also shows a reference table of weights from 50% to 100% of your 1RM, handy for planning training loads.
How to use
- Enter the weight you actually lifted.
- Enter the number of reps you performed with it.
- Your estimated 1RM and a percentage-based weight table are shown automatically.
How the calculation works
Your one-rep max (1RM) is the heaviest weight you can lift once with good form in a given exercise. This tool estimates it from a weight and the number of reps you completed, using the Epley formula: 1RM = weight ร (1 + reps รท 30) For a single rep, the weight lifted is already your 1RM, so it is shown as is. A table of 50% to 100% of the estimated 1RM is shown too. Training loads are usually set as a percentage of 1RM (%1RM). Common guidelines are 85% or more for 1โ5 reps for strength, 67โ85% for 6โ12 reps for muscle growth, and 67% or less for 12+ reps for muscular endurance.
Worked example
80 kg for 5 reps 1RM = 80 ร (1 + 5 รท 30) โ 93.3 kg From the table 90%: about 84.0 kg (strength: 3โ4 reps) 75%: about 70.0 kg (hypertrophy: 8โ10 reps) 60%: about 56.0 kg If you could do 10 reps at 80 kg, the estimate would be 80 ร (1 + 10 รท 30) โ 106.7 kg.
Things to be aware of
- Estimates get less accurate as reps increase, so the tool limits input to 20 reps. Sets of 10 or fewer give the best estimates.
- If you test a true 1RM, warm up thoroughly and use a spotter.
- Other formulas, such as Brzycki, exist and give results a few percent different.
FAQ
What is the Epley formula?
It's a widely used formula for estimating your one-rep max from a lifted weight and rep count: 1RM = weight ร (1 + reps รท 30).
How accurate is this estimate?
It's a statistical estimate that varies by individual and exercise. Use it as a general guideline โ if you want to actually test your 1RM, be sure to warm up thoroughly and have a spotter.
Why is the rep count capped at 20?
Estimation accuracy drops as the rep count increases, so it's limited to the range generally considered reliable (20 reps or fewer).