# One Rep Maximum Calculator

 Weight: Weight in: lbskg Reps: 1 2 3 4 5 6 7 8 9 10 Formula: Brzycki Epley Lander

The one rep max calculator below will help you determine the maximum poundage you can complete without necessarily having to do a one rep max lift. Simply enter the number of reps you can complete with the particular weight used. Once this information is entered, select formula and hit the calculate button.

One repetition maximum is the maximum weight one can lift on a particular exercise for a single repetition. Apart from being a measure of strength, it is sometimes used to determine fitness level. The one rep max calculation can also help while planning the weight one should lift. Supervision is recommended while performing since it can be dangerous. Testing of strength can be done in a laboratory and different tests have evolved. The one rep max is also known as Maximum Load (1RM).

Here is a simple chart that you can use.

Repetitions Squat
Bench press

1

1.0

1.0

1.0

2

1.0475

1.035

1.065

3

1.13

1.08

1.13

4

1.1575

1.115

1.147

5

1.2

1.15

1.164

6

1.242

1.18

1.181

7

1.284

1.22

1.198

8

1.326

1.255

1.232

9

1.368

1.29

1.232

10

1.41

1.325

1.24

How to calculate one rep max using the chart above:

weight lifted × chart number (locate under exercise type and reps completed) = one rep max

Let’s take an example of someone who benches 250 lbs for 6 repetitions. The one rep max is calculated as:

250 lbs × 1.18 = 295 lbs (this is the projected one rep max)

Alternatively, another chart has been developed that does not require any calculations.

Let’s look at our previous example that we calculated above to see if we obtain similar results.

Weight lifted:  250 lbs for 6 repetitions.

The repetitions appear on the top row while the weights are on the subsequent rows and columns. In our case, we find 250 lbs on the first column (almost at the end of the chart, marked yellow). Then we find the 6th repetition on the first row, move along the column and row until fingers meet in a single cell. In our example, this brings us to 295 (marked red). This is the same 1RM we found earlier.

Brzycki’s equation (1993)

1RM = Weight ÷ (1.0278 – (0.0278 × number of repetitions))

Baechle equation (2000)

1RM = Weight × (1 + (0.033 × number of repetition))

Lander’s formula

1RM = (100 × Weight) ÷ (101.3 – 2.67123 × number of repetitions)

O’Conner’s formula

1RM = weight × (1 + 0.025 × number of repetitions)

Mayhew et. al formula

1RM = (100 × Weight) ÷ (52.2 + (41.9 × e-0.055 × number of repetitions))

Wathan’s formula

1RM = (100 × Weight) ÷  (48.8 + (53.8 × e-0.075 × number of repetitions))

Here is how to run the bench press test.  It requires; a spotter, bench, barbell and weights.

1. Athlete warms up for about 10 minutes.
2. The spotter counts the number of bench presses that are done successfully.
3. Next, the athlete bench presses until they are unable to do anymore.
4. The spotter counts the number of benches that are done successfully.
5. If the number of bench presses exceeds 8, the athlete is allowed to rest for ten minutes while the weight is increased. The test is repeated again.
6. Using the maximum load calculator, the instructor can then calculate the 1 rep max of the athlete.