One Rep Max Calculator

Estimate your 1RM from any hard set, get your training percentages, and see how your lift stacks up for your bodyweight.

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KlickWay personal trainers program your lifts around these exact percentages - and make sure your form is ready before the weight gets heavy.

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How This 1RM Calculator Works

Both formulas estimate your one rep max from a submaximal set:

  • Epley: 1RM = weight x (1 + reps / 30). The most widely used estimate; the headline number and percentage table use it.
  • Brzycki: 1RM = weight x 36 / (37 - reps). Tends to run slightly more conservative at higher reps.

For the best estimate, use a recent hard set of 2 to 6 reps taken close to failure with solid form. The strength standards table compares your estimated 1RM against common bodyweight-multiplier benchmarks for the squat, bench press, deadlift, and overhead press.

One Rep Max FAQ

What is a one rep max?

Your one rep max (1RM) is the most weight you can lift for a single rep with good form. It is the foundation of percentage-based strength programming.

How accurate are 1RM formulas?

The Epley and Brzycki formulas are typically within a few percent when calculated from a set of 2 to 6 reps. Accuracy drops as reps climb, which is why this calculator caps input at 10 reps.

Is it safe to test a true 1RM?

With experienced spotters and proper warm-up, yes - but most lifters never need to. An estimate from a hard set of 3 to 5 reps is safer and nearly as useful for programming.

How do I use training percentages?

Strength work typically lives at 80 to 90 percent or more of 1RM for low reps; muscle-building work at 65 to 80 percent for moderate reps. The percentage table gives you starting loads for each rep range.