One rep max or 1RM in weight training is the maximum amount of weight that a person can possibly lift for one repetition. – Wikipedia
One Rep Max is the short form of one repetition maximum and is abbreviated to 1RM or one-rep max. The term is used by powerlifters and bodybuilders to estimate the weight that can be lifted in for one repetition. Many powerlifters use a 1RM calculator to estimate their one-rep max for bench press, deadlift, or squat. Now let’s have a look at how to calculate your one-rep max.
How to Calculate your One Rep Max?
There are different formulas to calculate your one-rep max but keep in mind that these formulas just give you an estimate of your one-rep max. Here are the 5 most popular formulas to calculate your 1RM.
- Lombardi formula: Weight × (number of reps ^ 0.1)
- Epley formula: Weight × (1 + (0.0333 × number of reps))
- Brzycki formula: Weight × (36 / (37 – number of reps))
- O’Conner formula: Weight × (1 + (0.025 × number of reps))
- Wathen Formula: (1RM= 100w/ 48.8+53.8-0.075r)
You can use any formula to calculate your one-rep max as there is a slight difference in the result. For example, if you can bench 40 kg for 5 reps then 1RM is 46 according to formulas 1, 2, and 5 and 45 for formula 3 and 4. So you can use the Guz Fitness calculator which uses the Epley formula.
You can also calculate your other rep maxes for up to 10 RM. You should start lifting 60 to 70 percent of your one-rep max and then you can increase weight step by step. It is recommended that work with a personal trainer and avoid injuries.
Final Words
So the best way to calculate your 1RM is using an online calculator. You can also use given formulas if you don’t want to use an online calculator.
