One rep max calculator
Enter a weight and the number of clean repetitions you managed with it. This shows four different formulas rather than one, because they disagree with each other and you deserve to see by how much before you trust the number.
Nothing you type is sent anywhere. The calculation runs in your browser.
How wrong is this number likely to be
Two things decide that, and neither is which formula you prefer.
The first is how many reps you did. Reynolds and colleagues tested seventy people at 1, 5, 10 and 20 reps on the bench press and the leg press, and prediction was sharpest from a set of five. It got steadily worse as the reps went up, and their conclusion was blunt: no more than ten repetitions should be used in a linear equation to estimate a one rep max. A set of fifteen tells you about your endurance, not your maximum.
The second is which lift. In the same study the standard error of their bench press equation was about 3 kg. For the leg press it was about 16 kg. Same people, same day, same method — the lower-body estimate was several times rougher. Legs fatigue differently and the rep-to-load relationship is messier there, so treat a squat or deadlift estimate as a much wider band than a bench estimate, however confident the number above looks.
Practically: enter a set of three to five reps if you want the best estimate this page can give, treat anything above ten as a rough indication, and give your lower-body numbers more benefit of the doubt in both directions.
Why I would rather you did not test a true single
I competed in weight lifting and power lifting myself, and I still tell almost every member here to estimate rather than test. A genuine maximum single is a skill separate from the strength it measures, it is the riskiest set in any programme, and it tells you very little that a set of five does not already tell you.
The people who genuinely need a tested maximum are competitors who have to attempt one on a platform anyway. Everybody else is better served by the rule I actually coach by, which is that the weight goes up when the last repetition of a set still looks like the first. That rule protects a shoulder and a lower back that have to last another thirty years, and it produces the same progress with none of the risk.
The wider approach this sits inside is on the S R Gym method, and the barbell coaching itself on strength training in Surat.
One rep max: common questions
- What is a one rep max?
- It is the heaviest weight you could lift once with acceptable technique. Most training is programmed as a percentage of it, so knowing roughly where yours sits tells you what to put on the bar for a set of five or a set of ten.
- Should I actually test my one rep max?
- Most people should not, and I say that as somebody who competed in weight lifting and power lifting. A true single is a skill of its own, it carries the most risk of any set you will do, and it tells you very little that a calculated estimate does not. Estimate it from a set you can do well instead, and save real singles for people preparing to compete.
- How accurate is a one rep max calculator?
- Reasonably accurate up to about five or six repetitions and progressively less so beyond that. The formulas were built on averages and individuals vary a good deal in how many repetitions they can manage at a given percentage. Use the number to choose working weights rather than to set a personal record.
- Which formula does this use?
- It shows four, because they disagree and hiding that would be dishonest. Epley and Brzycki are the two most commonly used, Lander and Lombardi are shown alongside them, and the headline figure is the average of the four. Where they spread widely, that spread is itself telling you the estimate is soft.
- How do I use this to plan my sets?
- The table below the result converts your estimate into working weights. As a rough guide, sets of five sit near 85 percent, sets of eight near 75 percent, and sets of twelve near 65 percent. Pick the weight where the last repetition of the set still looks like the first, which is the rule I actually coach by.
- Can you check my technique before I load a bar?
- Yes, and that is the more useful thing to sort out first. A calculated maximum on a lift you cannot control is a number without much meaning. Both branches, Adajan and Katargam, and you are welcome to come and watch a session before deciding anything. Call +91 98790 69960.
An estimate is a planning tool rather than a record. Warm up properly, stop a set when technique breaks down, and get a coach to watch you before you take any lift close to a maximum.
Get the lift checked before you load it
Twenty minutes on the floor is worth more than any calculator. Call +91 98790 69960.
The research this page rests on
One reference rather than a row of them. The four formulas this page runs were published in coaching texts and physical-education journals that PubMed does not index, so there is no primary record to link for them, and inventing one would be worse than saying so.
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Journal of Strength and Conditioning Research, Reynolds JM, Gordon TJ and Robergs RA, 2006 · 70 subjects (34 men, 36 women), aged 18 to 69, tested at 1, 5, 10 and 20RM on bench press and leg press
Prediction was most accurate from a 5RM and degraded as repetitions rose, and the authors conclude that no more than 10 repetitions should be used in linear equations to estimate a 1RM. The study also found upper and lower body are not comparable: the standard error of their bench press equation was 2.98 kg against 16.16 kg for the leg press, so a lower-body estimate is several times rougher than an upper-body one from the same quality of input.