Calculate Your One-Rep Max (1RM)
Use the calculator below for any lift to estimate your one-rep max based on the amount of weight you can lift on a given move, and the number of clean reps you can achieve before muscle failure.
Why do you need to calculate your 1RM?
Strength coaches set up programs with percentages based on your 1RM because they don’t know your actual strength level, but they know what percentages they want you to be using relative to your single-rep max. The calculator gives you all the relevant loads, which are done simply by multiplying the percentage by your 1RM.
Let’s say you know you can lift 225 pounds for 10 reps—and only 10 reps, with good form—on the bent-over row. Based on that we can estimate not just your one rep max (100% of your 1RM), but other loads as well: your 85% 1RM , 70% 1RM , or 55% 1RM , depending on what your program calls for.
The calculator estimates your one-rep max based on the amount of weight you can lift on a given move, and the number of clean reps you can achieve before muscle failure. Let’s try it for the row, assuming you can do 225 pounds for 10 reps. Plug that into the calculator above. It’ll show your estimated 1RM to be 300 pounds.