You Asked: 'How Do I Find My One Rep Max?'


By: , SparkPeople Blogger
  :  5 comments   :  30,954 Views

Your One Rep Max is the highest possible weight you can lift for exactly one repetition. You can use the One Rep Max as a benchmark to measure strength gains over time. However, keep in mind that this metric is typically used on very specific, more advanced lifts like bench press and back squat, so you wouldn't use this metric on, say, a bicep curl or a calf raise. 

Some advanced athletes find their 1 RM by progressively bumping up their resistance until they fail the lift on the second repetition of a set. However, this method is risky and should be done with additional supervision. So how does a beginning lifter determine his or her One Rep Max?

As a beginner, the safest way to determine your 1 RM is to find your predicted 1 RM. The predicted 1 RM is a much safer option that lets you lift a lighter weight (something you can lift for up to 10 repetitions), then multiplies the weight you lifted by the coefficient (from the chart below) associated with the number of reps you completed.

(Formula courtesy of

Total Reps Completed Squat or Leg Press Coefficient Chest Press Coefficient
1 1 1
2 1.0475 1.035
3 1.13 1.08
4 1.1575 1.115
5 1.2 1.15
6 1.242 1.18
7 1.284 1.22
8 1.326 1.255
9 1.368 1.29
10 1.41 1.325

Example: Say you can consistently bench press 100 pounds and fail at 8 reps. Find the coefficent (from the chest press column) that corresponds with 8 reps above. In this example, that is 1.29. Multiply that coeffient by the amount of weight you lifted:

1 RM = 100 pounds x  1.255 = 125.5 pounds

This tells you that your predicted 1 RM for bench press is 125.5 pounds. This means that 125.5 pounds is the estimated maximum amount of weight you could lift for exactly one repetition. Fitness professionals recommend that you try to lift at 60-70% of your 1 RM for up to 15 reps per set in order to build strength. (As you become stronger and are able to lift more than 15 reps at that weight, you can increase the amount of weight you lift.) However, remember that the 1 RM test is not the only way to find a good starting point for lifting. Using trial and error to find a weight that fatigues your muscles after 8-15 repetitions can be just as effective.

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  • 5
    Somehow, this doesn't seem detailed enough for serious lifters or informative enough for beginners. I feel like I've missed a reel. Acefitness or even Muscle & Fitness have clearer explanations. Spark is usually so good at explaining fitness info! - 6/7/2015   12:40:54 PM
  • 4
    "You wouldn't use this metric on, say, a bicep curl or a calf raise." Well, what DO you use for bicep curls or calf raises? Trial and error? A different metric? Most people, especially beginner weight lifters, would read this article to figure out what to do for that type of exercise and this information is not useful in that context. - 4/14/2015   11:45:32 AM
  • 3
    I totally stopped reading mid-article because I was confused. - 2/2/2015   1:17:24 PM
  • 2
    Yes! I lift what I can repeat for 12 reps and yet feel the work involved, and I do 15 reps. Of course over time, that weight lacks the feeling of effort as I exerted before, so I up the weight by 5 lbs or so. This article was a bit much for this average person. - 1/4/2015   11:13:19 AM
  • 1
    Was anyone confused by this article. I have done some strenght training before, but I'm not a body builder. I don't think the information was presented for the average person. - 9/15/2014   11:40:06 PM

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