1RM calculator: your estimated one-rep max
Calculate your one-rep max on the bench press, squat, deadlift or pull-ups with Epley, Brzycki, RIR or RPE, in kg or lb. Below you'll find your training weights from 50 to 100%.
It's an estimate, not a test of your max: above 10 reps the formulas lose accuracy.
Take it to your routine. In Mobbe you log your sets and see your estimated 1RM on every exercise, for free.
Working weights and 1RM percentages
They update with the calculator. Right now they show a 1RM of 114.6 kg.
| % 1RM | Weight | To load | Reps |
|---|---|---|---|
| 50% | 57.3 kg126.3 lb | 57.5 kg | — |
| 55% | 63 kg138.9 lb | 62.5 kg | — |
| 60% | 68.8 kg151.7 lb | 70 kg | — |
| 65% | 74.5 kg164.2 lb | 75 kg | — |
| 70% | 80.2 kg176.8 lb | 80 kg | — |
| 75% | 86 kg189.6 lb | 85 kg | 10 |
| 80% | 91.7 kg202.2 lb | 92.5 kg | 8 |
| 85% | 97.4 kg214.7 lb | 97.5 kg | 5 |
| 90% | 103.1 kg227.3 lb | 102.5 kg | 3 |
| 95% | 108.9 kg240.1 lb | 110 kg | 2 |
| 100% | 114.6 kg252.6 lb | 115 kg | 1 |
| Reps | Epley | Brzycki |
|---|---|---|
| 1 | 100% | 100% |
| 2 | 93.8% | 97.2% |
| 3 | 90.9% | 94.4% |
| 4 | 88.2% | 91.7% |
| 5 | 85.7% | 88.9% |
| 6 | 83.3% | 86.1% |
| 7 | 81.1% | 83.3% |
| 8 | 78.9% | 80.6% |
| 9 | 76.9% | 77.8% |
| 10 | 75% | 75% |
| 11 | 73.2% | 72.2% |
| 12 | 71.4% | 69.4% |
“To load” rounds to 2.5 kg, what you can put together with plates. Reps come from Epley and are shown up to 12.
Your 1RM on the bench press, squat, deadlift and overhead press
The same calculator, set up for each exercise, with what to know before you test your max.
How we calculate
The formulas, with the worked example. Epley is the same one the Mobbe app uses.
- Step 1
Epley
The formula the Mobbe app uses for your estimated 1RM. With 1 rep, your 1RM is the weight you lifted. In the example (100 kg × 5 reps to failure): 100 × (1 + 5 ÷ 30) = 116.7 kg.
1RM = weight × (1 + reps ÷ 30)Epley, 1985. - Step 2
Brzycki and the average
The second most used formula: 100 × 36 ÷ (37 − 5) = 112.5 kg. Your estimated 1RM is the average of the two: 114.6 kg. We accept 1 to 12 reps; above 10, the formulas lose accuracy.
1RM = weight × 36 ÷ (37 − reps)Brzycki, 1993. Accuracy on the bench press, squat and deadlift: LeSuer, 1997. - Step 3
RIR and RPE
If you didn't reach failure, we add the reps you had left (RIR). RPE is 10 minus RIR: RPE 8 is 2 in reserve. 100 kg × 5 at RPE 8 counts as 7 reps to failure: 121.7 kg (Epley 123.3, Brzycki 120).
reps to failure = reps done + RIRZourdos, 2016; Helms, 2016. - Step 4
Pull-ups and dips
The 1RM is calculated on your weight plus the added weight, and then your weight is subtracted to give you the max added weight. At 80 kg and 6 pull-ups with 10 kg: 106.3 kg in total, about 26.3 kg of max added weight.
max added weight = 1RM (your weight + added weight) − your weightEpley, 1985; Brzycki, 1993.
Sources
- Epley B. Poundage chart. Boyd Epley Workout. Lincoln, NE: Body Enterprises; 1985.
- Brzycki M. Strength testing: predicting a one-rep max from reps-to-fatigue. J Phys Educ Recreat Dance. 1993;64(1):88-90.
- LeSuer DA, McCormick JH, Mayhew JL, Wasserstein RL, Arnold MD. The accuracy of prediction equations for estimating 1-RM performance in the bench press, squat, and deadlift. J Strength Cond Res. 1997;11(4):211-213.
- Zourdos MC, Klemp A, Dolan C, et al. Novel resistance training-specific rating of perceived exertion scale measuring repetitions in reserve. J Strength Cond Res. 2016;30(1):267-275. doi:10.1519/JSC.0000000000001049
- Helms ER, Cronin J, Storey A, Zourdos MC. Application of the repetitions in reserve-based rating of perceived exertion scale for resistance training. Strength Cond J. 2016;38(4):42-49.
Frequently asked questions
What is 1RM?
It's your one-rep max: the heaviest weight you can lift once, with good technique, on an exercise. It helps you choose your training weight as a percentage, for example 75% for sets of about 10 reps.
How do I calculate my 1RM without testing it?
With a set of 1 to 12 reps. With Epley: weight × (1 + reps ÷ 30). If you lift 100 kg 5 times to failure, your estimated 1RM is 116.7 kg with Epley and 112.5 kg with Brzycki; the calculator shows the average, 114.6 kg.
Which formula is more accurate, Epley or Brzycki?
Neither is equally right for everyone. Below 10 reps Epley gives a bit more, at 10 they match, and above that Brzycki gives more (with 100 kg × 12: Epley 140 and Brzycki 144 kg). Above 10 reps both lose accuracy (LeSuer 1997): the heavier the set, the better the estimate.
How do I calculate 1RM with RPE or RIR?
Add the reps you had left in reserve (RIR) to your reps. RPE is 10 minus RIR: RPE 8 is 2 in reserve. 100 kg × 5 at RPE 8 counts as 7 reps to failure and gives a 1RM of 121.7 kg.
How do I calculate my pull-up 1RM?
Choose "Bodyweight" and enter your body weight, the added weight (0 if you don't use any) and the reps. At 80 kg and 6 pull-ups with 10 kg added, your total 1RM is 106.3 kg and your max added weight, about 26.3 kg.
Does it work for the bench press, squat and deadlift?
Yes. The accuracy of these formulas was studied precisely on the bench press, squat and deadlift (LeSuer 1997), and they're used the same way on other barbell, dumbbell or machine exercises.
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Mobbe builds your plan with these numbers
Download Mobbe for free: it builds your routine with AI, you log every set and the app estimates your 1RM on every exercise so you know what weight to use next.
