One Rep Max Calculator
Calculate your one-rep max (1RM) for your lifts. Just plug in your working weight and the number of reps for any exercise
Your Projected One Rep Max is: {{result}} {{unitLabel}}
| Percentage of 1RM | Weight | Reps |
|---|---|---|
| 100% | {{result.toFixed(1)}} {{unitLabel}} | 1 |
| 95% | {{(result * 0.95).toFixed(1)}} {{unitLabel}} | 2 |
| 90% | {{(result * 0.90).toFixed(1)}} {{unitLabel}} | 4 |
| 85% | {{(result * 0.85).toFixed(1)}} {{unitLabel}} | 6 |
| 80% | {{(result * 0.80).toFixed(1)}} {{unitLabel}} | 8 |
| 75% | {{(result * 0.75).toFixed(1)}} {{unitLabel}} | 10 |
What is a One-Rep Max?
The one rep max (1RM) is the maximum amount of weight you can lift for one repetition of an exercise. It's like estimating the heaviest thing you can lift once without hurting yourself.
The Brzycki calculation helps you figure out your 1RM without having to actually lift the heaviest weight. You use a lighter weight and do as many reps as you can. Then, you use this formula to estimate your 1RM:
For example, if you can lift 50 pounds 5 times, you plug it into the formula like this:
This helps you estimate your 1RM safely without lifting a super heavy weight just once.
Can I just warm up and hit my estimated 1RM?
No, not necessarily. The estimated one-rep max is only an estimate. Some lifters will find they can only lift less than it, others will find they are stronger than the formula’s estimates. Lift at your own risk.
What's the point of 1RM if it's not accurate?
You can use your projected 1RM to help you train different volumes depending on your goals. For example training at 85% of your 1RM for 6 repetitions.