1RM Calculator: Estimate Your One Rep Max
Enter the weight you lifted and the reps you completed. Get your estimated one-rep max, a full rep-max chart and training percentages, in lb or kg.
TL;DR
Your one-rep max (1RM) is the heaviest weight you can lift once with good form. Enter the weight and reps from a hard set and this calculator averages seven proven formulas, Epley, Brzycki, Lander, Lombardi, Mayhew et al., O'Conner et al. and Wathan, into one estimate, plus a rep-max chart and training percentages.
Estimated 1RM
260 lb
Average of 7 formulas, from 225 lb x 5 reps.
Your rep maxes
| Reps | Weight |
|---|---|
| 1 | 260 lb |
| 2 | 247 lb |
| 3 | 242 lb |
| 4 | 234 lb |
| 5 | 226 lb |
| 6 | 221 lb |
| 7 | 216 lb |
| 8 | 208 lb |
| 9 | 200 lb |
| 10 | 195 lb |
| 11 | 182 lb |
| 12 | 174 lb |
| 15 | 169 lb |
Training percentages
| % of 1RM | Weight |
|---|---|
| 100% | 260 lb |
| 95% | 247 lb |
| 90% | 234 lb |
| 85% | 221 lb |
| 80% | 208 lb |
| 75% | 195 lb |
| 70% | 182 lb |
| 65% | 169 lb |
| 60% | 156 lb |
| 55% | 143 lb |
| 50% | 130 lb |
Estimate by formula
| Formula | Estimated 1RM |
|---|---|
| Epley | 263 lb |
| Brzycki | 253 lb |
| Lander | 256 lb |
| Lombardi | 264 lb |
| Mayhew et al. | 268 lb |
| O'Conner et al. | 253 lb |
| Wathan | 262 lb |
Watch your estimated 1RM climb
PR Streak tracks your estimated 1RM automatically from the sets you log, right alongside every heaviest weight and best set volume PR.
What is a 1RM?
Your one-rep max, or 1RM, is the most weight you can lift for one full repetition of an exercise with good form. It's the standard measure of maximal strength, and most strength programs set training weights as a percentage of it: "5 sets of 5 at 80%" means 80% of your 1RM.
Testing a true max takes a toll and carries more risk than a normal training set. A hard set of several reps, taken close to failure, carries enough information to predict what you could lift once, which is what this one rep max calculator does.
How this 1RM calculator works
Enter the weight and reps from a set close to failure. The calculator runs that set through seven published 1RM prediction equations, and the big number is their average. A single rep is taken as your 1RM as-is. Some lifters call this a rep max calculator or max rep calculator, since it works the same way for the bench press, squat, deadlift or any other lift.
- Use a hard set. The estimate assumes the set was taken close to failure. Stopping well short of failure underestimates your 1RM.
- Keep it to 10 reps or fewer. The equations stay reasonably close up to about 10 reps and diverge quickly after that, which is why the calculator accepts at most 15.
- Estimate each lift separately. Your bench press, squat and deadlift maxes are independent, so treat this as a bench max calculator, squat max calculator or deadlift max calculator, one set at a time.
The seven 1RM formulas this calculator averages. w is the weight lifted, r is the reps completed.
| Formula | 1RM equation |
|---|---|
| Epley | w × (1 + r ÷ 30) |
| Brzycki | w × 36 ÷ (37 − r) |
| Lander | 100 × w ÷ (101.3 − 2.67123 × r) |
| Lombardi | w × r^0.10 |
| Mayhew et al. | 100 × w ÷ (52.2 + 41.9 × e^(−0.055 × r)) |
| O'Conner et al. | w × (1 + 0.025 × r) |
| Wathan | 100 × w ÷ (48.8 + 53.8 × e^(−0.075 × r)) |
One rep max chart: reps at each percentage
This one rep max chart, also called a 1RM chart, shows about how many reps you can typically complete at each percentage of your 1RM. It comes from the NSCA's percent-of-1RM table (Essentials of Strength Training and Conditioning). Use it to pick working weights or to sanity-check an estimate; individual results vary with the exercise and your training history.
Percent of 1RM and the reps typically completed at that load.
| % of 1RM | Reps you can typically complete |
|---|---|
| 100% | 1 |
| 95% | 2 |
| 93% | 3 |
| 90% | 4 |
| 87% | 5 |
| 85% | 6 |
| 83% | 7 |
| 80% | 8 |
| 77% | 9 |
| 75% | 10 |
| 70% | 11 |
| 67% | 12 |
| 65% | 15 |
How to use your 1RM in training
Once you have an estimated 1RM, the NSCA's training-load guidelines turn it into a target load and rep range for your goal.
NSCA training zones by goal.
| Goal | Load | Reps per set |
|---|---|---|
| Strength | 85% or more | 6 or fewer |
| Muscle size (hypertrophy) | 67-85% | 6-12 |
| Muscular endurance | 67% or less | 12 or more |
Treat the estimate as a starting point. If a prescribed weight feels far too easy or impossible for the reps, adjust it and re-estimate from that set.
Testing your 1RM safely
- Warm up with several progressively heavier sets of low reps before any heavy single. The plate calculator can build that ramp for you.
- Use a spotter or safety bars on the bench press and squat.
- Rest a few minutes between heavy attempts, and stop when your form breaks down.
How does your 1RM compare?
What counts as strong depends on your bodyweight, sex, age and experience. Check your strength percentile against raw competitive lifters, or see the full breakdown in our strength standards by bodyweight. To train around an estimate instead of a max, log your working sets with RPE so the effort behind each set stays visible.
Used by lifters following PPL, 5x5, upper/lower, and more.
Frequently Asked Questions
How accurate is a 1RM calculator?
It gives an estimate, not a measurement. Estimates from a set of about 10 reps or fewer, taken close to failure with good form, are the most dependable. Past that the formulas disagree more, and your true max also depends on the exercise, your technique and how practiced you are at heavy singles.
Which 1RM formula is most accurate?
No single formula is best for everyone. Epley and Brzycki are the most widely used, but each equation comes from a different study, so this calculator shows all seven and uses their average as your estimated 1RM.
What percentage of my 1RM should I train with?
It depends on your goal. NSCA guidelines put strength work at 85% of 1RM or more for 6 reps or fewer, muscle-building work at 67-85% for 6-12 reps, and muscular endurance work at 67% or less for 12 or more reps.
How often should I test my 1RM?
Many programs retest at the end of a training block, often every 8-12 weeks. In between, estimating your 1RM from regular working sets tracks your progress without the fatigue of a max attempt.
Can I use this as a bench press calculator, squat max calculator or deadlift max calculator?
Yes. The formulas don't care which exercise you used, only the weight and reps. Enter a set from your bench press, squat or deadlift and estimate each one separately, since your max on one lift says little about the others.
Does this 1RM calculator work in kg and lb?
Yes. The formulas work the same in any unit: enter the weight in the unit you lifted it in, pick lb or kg, and every result on the page comes back in that unit.
What is a good 1RM for my bodyweight?
It depends on your bodyweight, sex, age and training experience. Once you have an estimate here, see where it lands in our strength percentile calculator or the strength standards by bodyweight.
Sources
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