Free tool · For gym goers
Bench press calculator: your one rep max from any set you have already done
Enter the weight you lifted and how many reps you got, and this gives you your estimated one rep max plus the working weights for every rep range. No sign up, no email, and the same formula the BryksBuilt app uses to track your strength.
Work out your one rep max
Enter a set you have already done. Two to ten reps gives the most honest estimate.
Your estimated one rep max
216 lb
Based on 185 lb for 5 reps, using Epley.
What to put on the bar
Rounded to the nearest 5 lb, the way the app prescribes it.
- 2 reps200 lb
- 3 reps195 lb
- 5 reps185 lb
- 8 reps170 lb
- 10 reps160 lb
- 12 reps155 lb
Your one rep max is the heaviest weight you could lift once, and you almost never need to actually attempt it to know roughly what it is. Enter a set you have already done and the calculator above turns it into an estimate, plus the working weights for every rep range underneath.
This page is free, there is nothing to sign up for, and for any set of two reps or more the number you get here is the number the BryksBuilt app tracks for you, because both run Epley.
How the estimate works
The maths is Epley's formula, published in 1985 and still the most widely used:
estimated one rep max = weight multiplied by (1 + reps divided by 30)
So a set of 185 pounds for 5 reps gives 185 times 1.1667, which is about 216 pounds. A set of 225 for 3 gives 225 times 1.1, or about 248.
The shape of that formula tells you something useful on its own. Every extra rep you get with a given weight adds roughly three and a third percent to the estimate. That is why a single extra rep matters so much, and why chasing one more rep at the same weight is a real form of progress even when the number on the bar has not moved.
Why we only estimate between two and ten reps
Every one rep max formula is a curve fitted to real lifters, and every curve is only honest inside the range it was fitted on.
Below that range there is nothing to estimate. A single rep is already a max, so we hand it straight back rather than inflating it.
Above ten reps the estimate quietly stops being about strength. A set of twenty is a test of how much discomfort you can tolerate and how efficient your breathing is, and the formulas do not know the difference. They keep multiplying, and they hand you a number twenty or thirty pounds higher than anything you could actually unrack. The BryksBuilt app enforces the same two to ten window when it tracks your estimated max, which is why this page does too.
What to do with the number
The estimate is only useful if it changes what you put on the bar. The standard way to use it is as a percentage.
Most strength work sits between 70 and 90 percent of your max. Pure strength triples and singles live at 85 to 95. Hypertrophy work, the kind that actually builds size, sits around 65 to 80 percent for sets of eight to twelve. The table below does that arithmetic for you at every rep count.
One warning worth more than the table. Your one rep max is not a fixed property of your body. It moves with sleep, with how much you have eaten, with how far into a training block you are, and with how warm you are. A number that was right in March can be five percent off in June in either direction. Re estimate every four to six weeks from a real set rather than assuming the old number still holds.
The three formulas, and why they disagree
Epley is not the only option. The two you will run into most often are Brzycki, which is weight times 36 divided by 37 minus reps, and Lombardi, which is weight times reps to the power of 0.10.
They drift apart more than people expect. From a set of 225 for three, Epley says 248, Brzycki says 238 and Lombardi says 251, a spread of 13 pounds. At ten reps Brzycki and Epley land on exactly the same number, 300, because 36 over 27 and one plus ten over thirty are both four thirds, while Lombardi drops to 283. Nobody has settled which is most accurate, because the honest answer is that it varies by lifter, by lift, and by how much bench pressing you have done in your life. The table further down shows all three side by side.
We use Epley for one plain reason: it is what the app uses, and a calculator that disagreed with your own training history would be worse than useless. The comparison table further down is there so you can see the spread rather than trusting any single number more than it deserves.
Tracking it is the part that matters
A one rep max estimate on its own is trivia. The same estimate taken every month for a year is the clearest picture of your training you will ever have, because it turns a hundred scattered sets into one line that either goes up or does not.
That is the part a calculator cannot do for you. BryksBuilt logs every set, works out your estimated max on the lifts you actually train, and shows you the trend over time along with your meals, your programs and everything else. It is free to download.
Percentage of your max, by reps
This is the same table the calculator uses, worked out ahead of time so you can read it without entering anything. A lifter with a 225 pound bench should expect about 195 pounds for a set of five and about 170 pounds for a set of ten. A single rep is 100 percent of your max by definition, which is why the table starts at two.
| Reps | Percent of your one rep max | Example, 225 lb max | What it is for |
|---|---|---|---|
| 2 | 93.8% | 210 lb | Peak strength |
| 3 | 90.9% | 205 lb | Peak strength |
| 4 | 88.2% | 200 lb | Strength |
| 5 | 85.7% | 195 lb | Strength |
| 6 | 83.3% | 190 lb | Strength |
| 8 | 78.9% | 180 lb | Size and strength |
| 10 | 75% | 170 lb | Size and strength |
| 12 | 71.4% | 160 lb | Size and technique work |
Percentages come from Epley, the formula the calculator above uses and the one BryksBuilt prescribes working weights with. Round to the nearest 5 pounds or 2.5 kilos, because that is what the plates let you do.
The three formulas, side by side
What each formula estimates from the same set of 225 pounds. They agree closely in the middle and drift apart at both ends, and nobody has settled which is most accurate because the honest answer is that it varies by lifter and by lift.
| Reps | Epley, what we use | Brzycki | Lombardi | Spread |
|---|---|---|---|---|
| 1 | 233 lb | 225 lb | 225 lb | 8 lb |
| 3 | 248 lb | 238 lb | 251 lb | 13 lb |
| 5 | 263 lb | 253 lb | 264 lb | 11 lb |
| 8 | 285 lb | 279 lb | 277 lb | 8 lb |
| 10 | 300 lb | 300 lb | 283 lb | 17 lb |
Brzycki and Lombardi are here for comparison only. BryksBuilt uses Epley everywhere, so the calculator above and your training history in the app are always the same number. Note the row for a single: Epley estimates above the weight you actually lifted, which is why the calculator hands a true single straight back instead of running the formula on it.
Free to download
Knowing the number is the easy part
Hitting it four days out of five for a year is the whole job. BryksBuilt tracks your workouts, your food and your progress in one place, and it is free to download.
iPhone and Android. No card needed to start.
Questions people ask
The short answers
How accurate is a one rep max calculator?
Close enough to program with, and not close enough to attempt blind. Estimates from sets of two to five reps land within a few percent for most lifters. Past about ten reps the error grows fast, because at that point you are measuring muscular endurance as much as maximal strength. Treat the number as a starting point for your working weights, not as a lift you have banked.
Which formula does this use?
Epley, which is weight multiplied by one plus reps divided by thirty. It is the same formula the BryksBuilt app tracks your estimated max with, so for any set of two reps or more the number here and the number in your app are the same number. There is one deliberate difference and it is on a true single: this page hands a single straight back, because if you lifted it once then that is your max and there is nothing to estimate. There is a table further down comparing Epley with Brzycki and Lombardi, the other two formulas you will meet, which disagree by anywhere from 8 to 17 pounds depending on the rep count.
Why does it only accept two to ten reps?
Because outside that window the estimate stops being honest. A single rep is already a max and needs no maths, so this page returns it as it is. Above ten reps, fatigue and technique breakdown dominate the result and every formula overestimates. The app enforces the same two to ten window on the sets it will estimate from, for the same reason.
Should I actually test my one rep max?
Most people do not need to. A true max attempt is a skill of its own, it needs a spotter and a warm up you have planned, and it costs you several days of recovery. If you are not competing in powerlifting, estimating from a heavy set of three to five is safer, repeatable, and tells you what you actually need to know.
Does this work for squat and deadlift too?
Yes. The formula does not know which lift you are doing. Bench tends to estimate slightly high and deadlift slightly low, because deadlifts drop off faster as reps climb, so take the deadlift number with a little more caution.
Why is my calculated max higher than what I can actually lift?
Usually one of three reasons. The set was not genuinely to failure, so the reps you entered were not the reps you had left. The rep count was high enough that endurance carried you. Or you are comparing a fresh estimate against a max attempt made at the end of a session. All three are normal.
Where the numbers come from
Every competitor price on this page was read on the company's own pricing page on the date shown. Prices change; if one has, email support@bryksbuilt.com and we will fix it the same week.
- apps.apple.com/app/id6760272101: “BryksBuilt: Fitness Tracker, free to download with an in app Pro subscription” (checked September 10, 2026)
Keep reading
Become someone who trains.
Workouts, meal plans, recipes, grocery lists and a coach in your pocket. Free to download.
Free to downloadWorkouts, meals and a coach in one appiPhone and Android