1 Rep Max Calculator

Weight Lifted Reps


Your One-Rep Max (one-rm): ?


95% one-rm 70% one-rm
90% one-rm 65% one-rm
85% one-rm 60% one-rm
80% one-rm 55% one-rm
75% one-rm 50% one-rm

The 1 Rep Max Calculator is a must have tool for every weight lifter. It calculates the maximum weight that you can lift for 1 repetition given information that you already know. Just enter the weight and reps that you were previously able to achieve and let the Your Fitness Tool® 1RM Calculator do the rest! It can also be used to calculate the percentages of your one rep max.

We developed the 1 Rep Max Calculator for anyone that wants to continue to improve their performance and their physique. If you want to make progress in the gym, it’s important to track the weight you are lifting. Log your best 1 rep max for every exercise and keep track of your progress.

How To Calculate your 1 Rep Max

Let’s say you know you can lift 225 pounds for 10 reps, with perfect form, on the Deadlift Exercise. Based on that we can estimate not only 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 current workout program requires.

The 1RM calculator estimates your one rep max based on the amount of weight you can lift on a specific movement, and the number of clean reps you can achieve before muscle failure. For example, let’s try it for the deadlift, assuming you can do 300 pounds for 10 reps. Input that into the calculator above. It’ll show your estimated 1RM to be 400 pounds.

How To Use Your 1 Rep Max In A Workout Programme

Personal Trainers and online coaches usually set up workout programs with percentages based on your 1RM because they don’t always know your actual strength level, but they know what percentages they want you to be using relative to your single-rep max. The Your Fitness Tools® 1 rep max calculator gives you all the relevant loads, which are done simply by multiplying the percentage by your 1RM (in this case, 250 pounds). For example, if you want to do 80% of your 1RM, the calculator tells you to use 200 pounds (which is simply 0.85 x 200).

Some programs are set up a little differently and will instead tell you to do your 3RM, 6RM, or some other number. What’s different here is that instead of a giving you a percentage of your one-rep max, you’ll see 3RM, which indicates you should use a weight that you can do for three and only three reps. You’ll need the table below to essentially do the conversion in a different way.

Let’s say your strength workout requires  you to use your 3RM and 5RM for sets of Barbell Squats. Say you know you can do 245 pounds for 8 reps, but you don’t know your one-rep max. If you can just do 8 reps with good form, look at the chart and see that 8 means you’re working at 80% of your 1RM (80% 1RM).

Start by computing your 1RM; just divide 245 pounds by 0.80, which estimates your single-rep max to be 306.25, which can be rounded down to 305. To find your 3RM, note that 3 corresponds to 93% 1RM, so multiply 305 x 0.93, which estimates your working weight to be 285 (rounded up) pounds. Your 5RM would be 305 x 0.87, giving you a working weight of roughly 265 pounds.

The same program that asked you to do your 3RM and 5RM could alternately have said to do 93% 1RM and 87% 1RM, respectively. Those working weights are exactly the same as you can see in the chart below.

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