One Rep Max Calculator
Enter the weight and reps of a set you took to failure. You get your estimated one-rep max (1RM) from seven published formulas, each formula's own number, your 3-, 5- and 10-rep maxes, a training max and a full rep table.
Estimated 1RM 259.9 lb average of 7 formulas for 225 lb × 5 reps
| Formula | 1RM (lb) | Rep range given |
|---|---|---|
| Epley | 262.5 | up to 10 |
| Brzycki | 253.2 | up to 10 |
| Lander | 255.8 | not specified |
| Lombardi | 264.3 | up to 11 |
| Mayhew et al. | 267.8 | up to 15 |
| O'Connor et al. | 253.1 | not specified |
| Wathen | 262.3 | not listed |
| 3RM | 5RM | 10RM |
|---|---|---|
| 237.7 lb | 225.0 lb | 198.3 lb |
| 85% | 90% | 95% |
|---|---|---|
| 220.9 lb | 233.9 lb | 246.9 lb |
| Reps | % of 1RM | Weight (lb) |
|---|---|---|
| 1 | 100.0% | 259.9 |
| 2 | 94.3% | 245.0 |
| 3 | 91.5% | 237.7 |
| 4 | 88.9% | 231.1 |
| 5 | 86.6% | 225.0 |
| 6 | 84.4% | 219.2 |
| 7 | 82.2% | 213.7 |
| 8 | 80.2% | 208.4 |
| 9 | 78.2% | 203.2 |
| 10 | 76.3% | 198.3 |
The seven 1RM equations and their rep ranges
Each equation turns a set to failure into a 1RM; w is the weight lifted and r the reps. They are taken as printed in two peer-reviewed papers that compare them, Reynolds et al. (2006) and Mayhew et al. (2008). The rep ranges are the ones Reynolds et al. list for each author's equation.
| Formula | 1RM = | Published | Rep range given |
|---|---|---|---|
| Epley | w × (1 + r ÷ 30) | 1985 | up to 10 |
| Brzycki | w ÷ (1.0278 − 0.0278 × r) | 1993 | up to 10 |
| Lander | 100 × w ÷ (101.3 − 2.67123 × r) | 1985 | not specified |
| Lombardi | w × r0.10 | 1989 | up to 11 |
| Mayhew et al. | 100 × w ÷ (52.2 + 41.9 × e−0.055 × r) | 1992 | up to 15 |
| O'Connor et al. | w × (1 + 0.025 × r) | 1989 | not specified |
| Wathen | 100 × w ÷ (48.8 + 53.8 × e−0.075 × r) | 1994 | not listed |
Reynolds et al. print Epley's factor as 0.033 per rep; this calculator uses 1 ÷ 30 (0.0333…). At 10 reps the two differ by 0.25%.
The default result is the average of all seven. A single rep is a different case: the result is simply the weight you lifted. Brzycki and Lombardi give exactly that weight for one rep, while the others put it higher, from 1.3% (Wathen) to 8.9% (Mayhew et al.).
Which sets give the most useful estimate
Reynolds et al. (2006) tested 70 adults on the barbell bench press and a plate-loaded leg press. Of the 5-, 10- and 20-rep maxes they measured, the 5-rep max predicted the 1RM best, and the error grew with the number of reps. They concluded that no more than 10 reps should be used with linear equations.
Mayhew et al. (2008) tested 103 college women on the bench press before and after 12 weeks of training. Several equations estimated the 1RM acceptably, and the estimates were better when the set had fewer than 10 reps.
That is why the calculator accepts 1 to 10 reps, the range given for Epley and Brzycki. Both studies used sets taken to failure, so enter a set where one more rep was not possible.
How many reps you can do at 75%, 80% and 90% of 1RM
Solved for reps, each equation tells you how many reps to failure a percentage of your 1RM allows. The seven agree closely near your max and spread out as the weight gets lighter.
| Formula | 95% | 90% | 85% | 80% | 75% |
|---|---|---|---|---|---|
| Epley | 1.6 | 3.3 | 5.3 | 7.5 | 10.0 |
| Brzycki | 2.8 | 4.6 | 6.4 | 8.2 | 10.0 |
| Lander | 2.4 | 4.2 | 6.1 | 8.0 | 9.8 |
| Lombardi | 1.7 | 2.9 | 5.1 | 9.3 | 17.8 |
| Mayhew et al. | 1.9 | 4.5 | 7.5 | 11.1 | |
| O'Connor et al. | 2.1 | 4.4 | 7.1 | 10.0 | 13.3 |
| Wathen | 2.0 | 3.6 | 5.3 | 7.3 | 9.6 |
Empty cell: Mayhew et al.'s equation gives 91.9% at 1 rep and less after that, so no rep count of 1 or more reaches 95%.
Training max at 85, 90 and 95 percent
A training max is a fixed percentage of your 1RM that a program uses in place of the max itself. Jim Wendler's 5/3/1 bases its weights on 90% of the 1RM ("The calculations are based on 90% of it"). The calculator shows 85, 90 and 95% so you can match whatever your program asks for; for a 1RM of 300 lb those are 255, 270 and 285 lb.
Questions
How do I convert reps to 1 rep max?
Take a set to failure and put its weight and reps into a 1RM equation. With Epley, 1RM = weight × (1 + reps ÷ 30), so 200 lb for 8 reps gives 253.3 lb. The calculator above runs all seven equations; their average for 200 lb × 8 is 249.4 lb.
If I deadlift 225 for 5 reps, what is my 1RM?
About 260 lb. The average of the seven equations is 259.9 lb; single equations range from 253.1 lb (O'Connor et al.) to 267.8 lb (Mayhew et al.).
What is my max if I bench 135 for 7?
About 164 lb. The seven-equation average is 164.2 lb, with single equations from 158.6 lb (O'Connor et al.) to 167.4 lb (Wathen).
How many reps is 75% of 1 rep max?
Around 10 for most equations: Epley 10.0, Brzycki 10.0, Lander 9.8 and Wathen 9.6 reps to failure. Mayhew et al. say 11.1, O'Connor et al. 13.3 and Lombardi 17.8; the equations drift apart as the percentage drops.
What is 80% of my 1RM?
Your 1RM × 0.8: for a 1RM of 300 lb, 240 lb. By the equations, 80% is the weight you could lift for about 7 to 10 reps: Wathen 7.3, Mayhew et al. 7.5, Epley 7.5, Lander 8.0, Brzycki 8.2, Lombardi 9.3, O'Connor et al. 10.0.
How many reps with 90% of 1RM?
About 2 to 5 reps to failure, depending on the equation: Mayhew et al. 1.9, Lombardi 2.9, Epley 3.3, Wathen 3.6, Lander 4.2, O'Connor et al. 4.4, Brzycki 4.6.
How to calculate a training max?
Multiply your 1RM by the training-max percentage. Jim Wendler's 5/3/1 bases its weights on 90%, so a 300 lb 1RM gives a 270 lb training max. If you only have a rep set, the calculator estimates the 1RM first and shows 85, 90 and 95% of it.
How many reps to max out?
One: a max is the most you can lift for a single rep. To estimate it without a max attempt, use a set of up to 10 reps to failure. Reynolds et al. compared 5-, 10- and 20-rep maxes and found the 5-rep max predicted the 1RM best.
Sources
- Reynolds JM, Gordon TJ, Robergs RA. Prediction of one repetition maximum strength from multiple repetition maximum testing and anthropometry. J Strength Cond Res 20(3):584–592, 2006.
- Mayhew JL, Johnson BD, LaMonte MJ, Lauber D, Kemmler W. Accuracy of prediction equations for determining one repetition maximum bench press in women before and after resistance training. J Strength Cond Res 22(5):1570–1577, 2008.
- Original equations, as printed in the two papers above: Epley B, Poundage Chart, Boyd Epley Workout, 1985; Brzycki M, JOPERD 64(1):88–90, 1993 (doi:10.1080/07303084.1993.10606684); Lander J, NSCA Journal 6:60–61, 1985; Lombardi VP, Beginning Weight Training, 1989; Mayhew JL, Ball TE, Arnold MD, Bowen JC, J Appl Sport Sci Res 6(4):200–206, 1992 (doi:10.1519/00124278-199211000-00002); O'Connor B, Simmons J, O'Shea P, Weight Training Today, 1989; Wathen D, Load assignment, in Essentials of Strength Training and Conditioning, 1994.
- Wendler J. 5/3/1: How to Build Pure Strength. T-Nation.