How to estimate your 1RM without maxing out
Epley and Brzycki with worked examples, a reps-to-percentage table, when the estimates fail and how reps in reserve help.
Wodmark team Updated 14 Nov 2026 5 min read
Programming in percentages needs a 1RM, the most you can lift once. Testing it for real is tiring, carries some risk and is not always worth it, especially with people who are new to training. The alternative is to estimate it from a set of several reps. This is how, with which formulas, and when not to trust the result.
The two formulas
The two most used start from the weight of a set taken to failure or close to it, and how many reps you did:
- Epley: 1RM ≈ weight × (1 + reps / 30).
- Brzycki: 1RM ≈ weight × 36 / (37 − reps).
They give similar results and cross at 10 reps. Below 10, Epley gives a little more than Brzycki; above, the other way round.
Worked examples
| Set | Epley | Brzycki |
|---|---|---|
| 265 lb × 3 | 291.5 lb | 280.6 lb |
| 185 lb × 5 | 215.8 lb | 208.1 lb |
| 135 lb × 8 | 171 lb | 167.6 lb |
| 80 kg × 6 | 96 kg | 92.9 kg |
| 50 kg × 10 | 66.7 kg | 66.7 kg |
The gap between the two gives you an idea of the margin of error. At 3 reps it is about 11 lb; at 10, none, but that does not make a 10-rep estimate better: it is just where the two formulas meet.
You can do the maths in the «Estimate 1RM» tab of the free 1RM calculator: enter weight and reps and it shows both estimates at once, in kg or lb.
What percentage of your max each set is
The same formulas the other way round: how many reps you should manage at each percentage of your 1RM. Useful to check whether a recorded max still holds.
| Reps | % of 1RM (Epley) | % of 1RM (Brzycki) |
|---|---|---|
| 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 % |
| 8 | 78.9 % | 80.6 % |
| 10 | 75 % | 75 % |
If your recorded back squat max is 225 lb and you do 190 lb for 8 without grinding, that max is out of date.
When they fail
- By lift. They work best on basic strength lifts such as the squat, deadlift, bench press or strict press. In the snatch and clean and jerk the limit is usually technique, not strength: nobody does a set of 8 snatches to failure with good form, and an estimate from that says little.
- By person. Some athletes can grind out many reps at a high percentage and others cannot. The formulas are an average; for two people with the same true 1RM, the same set can give different estimates.
- If the set was not to failure. A set of 5 with three reps left in the tank underestimates your max. That is why it helps to know how many you had left, which comes next.
Reps in reserve (RIR)
You do not need to go to failure every time you test. An easier way is to note how many reps you had left when you racked the bar: that is RIR (reps in reserve), and its cousin RPE on a 1 to 10 scale (RPE 8 means two reps left).
For the estimate, add the reps you did and the ones you had left. If you do 175 lb × 5 with two left, work it out as 7: Epley gives about 216 lb. It works better with experience, because at first almost everyone misjudges what they have left. With an RIR of 0 to 3 the estimate is usually reasonable; beyond that it is hard to tell.
How often to recalculate
- At the end of each strength cycle, usually every 6 to 12 weeks.
- When the sets at a high percentage feel easy for two or three sessions in a row.
- After an injury or a long break, downwards.
In between, do not change your max every week for one good set: percentages lose their meaning if the reference keeps moving.
What to do with the result
An estimate does the same job as a tested max: working out your training weights. If you will use it at high percentages (90 % or more), take the lower of the two formulas. The maths and rounding to your box's plates are in how to turn 1RM percentages into weights, with a full table.
In the Wodmark app, when you finish a «Train» session it estimates the 1RM of each set with Epley (up to 10 reps). If that beats your max, the app suggests a new one and you decide whether to confirm it; it never changes on its own. More in your max and your weights.
Frequently asked questions
Which 1RM formula is most accurate?
None is for everyone. At low reps (2 to 6) they give close values; look at both and, for heavy work, use the lower one.
How many reps are best for estimating a 1RM?
Between 3 and 6. Fewer and you are close to testing the max anyway; more than 10 and the error is too big.
Can I estimate the 1RM of a clean or a snatch?
You can do the maths, but it is worth little: in the Olympic lifts technique rules. For those, a max tested on a good day is more useful, or work from your front squat or deadlift 1RM.
Run a box? In Wodmark each athlete sees their weights already worked out from their max and rounded to the box's plates.
Sources: Epley B., Poundage Chart, Boyd Epley Workout, 1985. Brzycki M., «Strength testing: predicting a one-rep max from reps-to-fatigue», Journal of Physical Education, Recreation & Dance 64(1), 1993. Zourdos M. C. et al., «Novel resistance training-specific rating of perceived exertion scale measuring repetitions in reserve», Journal of Strength and Conditioning Research, 2016.