1. Pick the lift
Choose a category, then the exercise. Bench variations start on Mayhew. Conventional and sumo deadlifts start on Brzycki. Everything else starts on Epley. Any lift keeps the average of all seven, which is the readout to trust first.
One rep max calculator
Enter the weight and the reps. Get an estimated one-rep max from seven formulas, a percentage chart, and a rep-max table, in kilograms or pounds.
No lift selected. Average of all seven formulas is the recommended readout.
Any lift
—lb
Average of 7 formulas
Compare formulas
| Formula | 1RM |
|---|---|
| Epley | — |
| Brzycki | — |
| Lombardi | — |
| Lander | — |
| Mayhew | — |
| O'Conner | — |
| Wathen | — |
Percentage chart
Loads round to 5 lb. Reps are the inverse of the average of the seven formulas.
| % of 1RM | Weight | Approx. reps |
|---|---|---|
| 100% | — | — |
| 95% | — | — |
| 90% | — | — |
| 85% | — | — |
| 80% | — | — |
| 75% | — | — |
| 70% | — | — |
| 65% | — | — |
| 60% | — | — |
| 55% | — | — |
| 50% | — | — |
Rep-max table
| Reps | Estimated load |
|---|---|
| 1RM | — |
| 2RM | — |
| 3RM | — |
| 4RM | — |
| 5RM | — |
| 6RM | — |
| 7RM | — |
| 8RM | — |
| 9RM | — |
| 10RM | — |
| 11RM | — |
| 12RM | — |
Warm-up sets
Enter a weight to build a warm-up toward that work set.
History
Saved in this browser only. Nothing is uploaded.
No logged sets yet. Use Log after a result.
1RM ≈ —Chart ↓
7 formulaskg / lbSaved in your browser only
Estimates only. Testing a true max carries risk; use a spotter or safety arms. Not medical advice.
How it works
How to use the one rep max calculator
2. Enter the set you did
Weight and reps. Use a set you finished with decent form, ideally 3–6 reps. If the set was not all-out, turn on RPE so the calculator adds the reps you left in the tank. Dumbbell fields want one dumbbell. Dips, pull-ups, and chin-ups want added weight only.
3. Read the estimate and the range
The big number is the formula you selected, or the average. Under it, each formula has its own line. The gap between the lowest and highest is the spread. A wide spread means the rep count was high or the equations simply do not agree. Do not average that away and call it precise.
4. Take a training percentage
The chart turns the estimate into loads from 100% down to 50%, rounded to plates. The rep-max table goes the other way: what a triple or a set of eight might weigh. Both follow the formula you left selected.
5. Log it here, or don't
Copy drops the result on your clipboard. Log keeps it in this browser only. There is no account. Next time, recent lifts sit above the tabs so you can rerun the same exercise without hunting.
More tools
Calculators
Bench press calculatorMax bench, variations, and a percentage chart.Open →Squat calculatorBack squat and front squat, with a percentage chart.Open →Deadlift calculatorConventional, sumo, and trap bar, with a percentage chart.Open →RPE calculatorWeight at a reps-and-RPE target, or a 1RM from a rated set.Open →DOTS calculatorBodyweight-adjusted powerlifting score.Open →Wilks calculatorOriginal Wilks score from body weight and total.Open →Strength level calculatorLift-to-bodyweight ratios, plus DOTS when you have a total.Open →Plate calculatorPlates per side for a target bar weight.Open →1RM percentage calculatorPercent of a max, or the percent a weight represents.Open →Warm-up sets calculatorBar to working weight, rounded to plates.Open →Rep max calculatorEstimated 1RM through 12RM from one max.Open →Training max calculatorA 90% training max and 5/3/1-style loads.Open →Powerlifting total calculatorSquat, bench, and deadlift, then DOTS and Wilks.Open →FFMI calculatorFat-free mass index from height, weight, and body fat.Open →VO2 max calculatorCooper 12-minute run or the heart-rate ratio estimate.Open →Heart rate zone calculatorPercent of max heart rate and Karvonen zones.Open →Steps to miles calculatorSteps and stride length to miles and kilometres.Open →Lbs to kg calculatorPounds and kilograms, exact factor.Open →
Still on this page
1RM by exercise
Every lift lives here. The buttons set that exercise in the calculator and jump back up. Nothing about a squat or a deadlift sends you to another URL.
Chest
Bench variations default to Mayhew, the equation built on college bench-press tests. Flat, incline, decline, and close-grip are separate maxes. Keep the set at 10 reps or under when you want a number you might actually press. Dumbbell bench takes the weight of one dumbbell. Weighted dips take added weight only.
- Bench Press. Flat barbell bench. Pause or touch-and-go changes the number, so stay consistent.
- Incline Bench Press. Set the bench and leave it there. Thirty degrees and forty-five degrees are not the same max.
- Decline Bench Press. Use a spotter. The bar path is short and the unrack is awkward.
- Close-Grip Bench Press. Hands just inside shoulder width is enough. A death grip on the smooth is a wrist problem, not a triceps one.
- Dumbbell Bench Press. One dumbbell only. Two 40s is not an 80 kg bench.
- Weighted Dips. Added weight only. Lean changes how much chest you get. Keep the same torso angle.
Shoulders
Presses use Epley. The range of motion is short, so a set of 10 is a worse stand-in for a single than it is on a squat. Strict overhead press and push press should never share a max: the legs add load the formula cannot see. Dumbbell shoulder press is one dumbbell.
- Overhead Press. Strict standing press. No knee bend. Seated is a different exercise.
- Push Press. A dip and drive adds load you did not press. Do not file it as a strict press max.
- Dumbbell Shoulder Press. One dumbbell. Seated removes leg drive that a standing press sometimes sneaks in.
Back
Conventional and sumo deadlifts default to Brzycki and should stay at 10 reps or fewer. A high-rep pull tells you about grip and position more than it tells you about a max. Rows, pulldowns, and weighted chins use Epley. Pull-ups and chin-ups want added weight only.
Deadlift
Conventional and sumo default to Brzycki because long sets of deadlifts wander off what a max pull feels like. Ten reps is already a lot. Straps, a belt, and a hitch change the lift, so keep the rules the same as the day you will use the number. Trap-bar pulls are usually heavier and use Epley. A Romanian deadlift estimate is a training load for a hinge, not a competition pull. If you want percentages of a deadlift max, use the deadlift calculator. Conventional, sumo, and trap bar stay there.
- Deadlift (Conventional). Conventional stance. Straps, belts, and hitching all change the result.
- Sumo Deadlift. Wide stance. Do not compare a sumo max with a conventional max as if they were one lift.
- Trap Bar Deadlift. Usually heavier than a straight bar because the load sits at your sides.
- Romanian Deadlift. Soft knees, bar close, stop when your back takes over. This is not a 1RM contest lift.
- Barbell Row. Pendlay and bent-over rows are different. This chip is the continuous bent-over row.
- Pendlay Row. Bar returns to the floor every rep. Torso closer to parallel than a typical bent-over row.
- Dumbbell Row. One dumbbell. Brace on a bench so the estimate is the row, not your lower back.
- Weighted Pull-Up. Added weight only. Optional body weight gives a rough system total.
- Weighted Chin-Up. Palms toward you. Added weight only.
- Lat Pulldown. Stack weight as labeled. Cable machines differ. Stay on one machine.
- T-Bar Row. Chest-supported and free-standing T-bars are different lifts.
Legs
Squats use Epley. Depth and bar position decide whether the number means anything next month, so write both down. Machines such as the leg press, leg extension, leg curl, and calf raise are often taken higher than 10 reps. Read those estimates as a way to pick a hard set, not as a competition max.
Back squat
A squat 1RM calculator is only as honest as the depth. High-bar and low-bar change the load people can stand up with, and a squat that stops well above parallel is a different exercise. Use a set in the rep range you can brace, usually 5 or under if you want a number close to a single. Front squats often fail in the rack before the legs quit, so a high-rep front squat underestimates a true front-squat max. Hack squat and leg press belong to the machine you used. Do not convert a leg press into a back squat. The squat calculator keeps back squat and front squat together.
- Back Squat. High-bar or low-bar, pick one and keep the same depth. A high squat is a different lift.
- Front Squat. Clean grip or crossed arms, but do not switch mid-cycle. Upright torso, full depth.
- Hack Squat. Enter the loaded weight the way your machine counts it. Do not compare across brands.
- Leg Press. Foot height changes the lift. Sled weight may or may not include the carriage.
- Leg Extension. Stack numbers are machine-specific. A true single is rarely worth the knee stress.
- Leg Curl. Higher reps are normal here. The formula is a load planner.
- Hip Thrust. Bar across the hips. A pad changes comfort, not the math, as long as the load is the bar plus plates.
- Walking Lunge. Total load. Steps per leg should be written down or the 'reps' number is meaningless.
- Bulgarian Split Squat. One leg at a time. Log the load and which leg. Do not double it and call it a squat.
- Calf Raise. Standing and seated calf raises load different muscles. Keep them separate.
Arms
Curls and extensions use Epley. They are small lifts with sloppy rep definitions. A swing on a curl or elbows that drift on a skull crusher changes the load more than the formula does. Dumbbell curls and hammer curls take the weight of one dumbbell.
- Barbell Curl. Standing barbell. If you lean, the estimate describes the swing, not the curl.
- Dumbbell Curl. One dumbbell. Alternating and simultaneous curls fatigue differently.
- Hammer Curl. One dumbbell, thumbs up. Often a bit heavier than a supinated curl.
- Triceps Extension. Overhead or pressdown. The formula does not know which joint angle you used.
- Skull Crusher. Lying extension. Elbows drifting forward makes it a press.
Olympic
Power clean, hang clean, clean and jerk, and snatch stay on Epley, with a hard warning. These lifts miss for technical reasons all the time. A formula trained on bench reps does not know a lost catch. Prefer heavy singles. If you must use reps, stay at five or under, and three or under on the snatch and clean and jerk.
- Power Clean. Catch above a full squat. Technique fails before a formula's assumption does.
- Hang Clean. Above the knee or mid-thigh are different starts. Write it down.
- Clean & Jerk. The jerk is often the limiter. A clean max is not a clean-and-jerk max.
- Snatch. Full squat snatch unless you say power snatch. They are different lifts.
Other
Any lift is the default. It does not assume a bar path. The recommended readout is the average of all seven formulas. Name the exercise in your own log so next month's set is the same one.
- Any lift. Use this when the lift is not in the list. Name it in your log.
Definition
What is a one rep max?
A one-rep max is the heaviest load you can lift once with the standard you set for that exercise. On a bench that might mean a touch on the chest and a locked-out finish. On a squat it includes a depth you are willing to count. The calculator does not watch the rep. It only does the arithmetic.
Most training weeks never need a true max. A hard set of five, read through a formula, is enough to set percentages for the next block. The cost of missing a single is higher than the cost of being 2 kg off on a spreadsheet. Read the longer definition in what a one rep max is, or the practical steps in how to calculate your 1RM.
The math
The 1RM formulas
Seven equations. w is the weight you lifted. r is the reps. M is the estimated one-rep max. If you enter one rep, every formula returns that weight. The average is the arithmetic mean of whichever formulas still return a number. Brzycki is dropped if the rep count gets so high the denominator collapses.
| Formula | Estimate | Weight for r reps |
|---|---|---|
| Epley | w × (1 + r / 30) | M / (1 + r / 30) |
| Brzycki | w × 36 / (37 − r) | M × (37 − r) / 36 |
| Lombardi | w × r^0.10 | M / r^0.10 |
| Lander | 100w / (101.3 − 2.67123r) | M × (101.3 − 2.67123r) / 100 |
| Mayhew | 100w / (52.2 + 41.9 × e^(−0.055r)) | M × (52.2 + 41.9 × e^(−0.055r)) / 100 |
| O'Conner | w × (1 + 0.025r) | M / (1 + 0.025r) |
| Wathen | 100w / (48.8 + 53.8 × e^(−0.075r)) | M × (48.8 + 53.8 × e^(−0.075r)) / 100 |
Epley is a straight line: each rep adds about 1/30 of the load. O'Conner is a shallower line, 2.5% per rep. Brzycki bends up and gets aggressive as reps climb. Lombardi uses a shallow power. Lander, Mayhew, and Wathen come from percent-of-max curves. Mayhew's curve was fit on the bench press, which is why bench variations start there. The sources and the disagreements are written out on the formulas guide.
Pick a formula and stay with it for a training block if you are comparing weeks. Switching from Epley to Brzycki on a set of 10 will look like you got stronger when you only changed the equation.
Limits
How accurate is a 1RM estimate?
Low-rep sets give tighter estimates than high-rep sets. That is the practical rule, and it does not need a fake percentage attached to it. LeSuer and colleagues tested seven prediction equations on the bench, squat, and deadlift in untrained college students. Correlations with the tested max were high, and the equations still missed in systematic ways. On the deadlift, every equation they tried underestimated the lift they actually tested. The paper is linked in how accurate these calculators are.
Two people can lift the same 100 kg for five and have different maxes. One grinds the fifth rep. The other had three left. The RPE toggle is there for that gap. It is still a guess. Bar speed, pause length, and a spotter's fingers are not in the formula.
Why bother
Use cases
- Set a training percentage for the next month without testing a single this week.
- Compare a bench set with an incline set without pretending they are the same max.
- Turn a rated set (reps plus RPE) into a load you can put on the bar.
- Build warm-up jumps toward the weight you plan to lift, rounded to real plates.
- Check a squat or deadlift number against a bodyweight ratio on the strength-level page, without a made-up rank.
Questions
FAQ
What do I type into the one rep max calculator?
Type the weight you lifted and how many reps you completed. Choose kilograms or pounds. The page estimates a one-rep max with seven published formulas and shows the average, plus a percentage chart.
Which formula should I use?
Start with the average of all seven. It does not pretend one equation is right. If you want a single formula, bench variations default to Mayhew, conventional and sumo deadlifts default to Brzycki, and other lifts default to Epley. You can override any of those.
Why do the formulas disagree?
They were fit on different groups and different lifts. At 1–5 reps they usually sit close together. Past 10 reps the curves pull apart, and Brzycki rises faster than Epley. That spread is the range shown under the result.
Is a calculated 1RM the same as a tested max?
No. A tested max is the heaviest single you actually lift. A calculated 1RM is a guess from a submaximal set. Use it to pick training loads. Test a true max only when you have a reason, a spotter or safety arms, and a setup you trust.
How many reps make a useful estimate?
Sets of about 3–6 reps usually give a tighter estimate than sets of 12 or more. The calculator still runs up to 20 reps and warns above 10. Olympic lifts are the exception: keep those tests to singles or very low reps, because misses are often technical.
What does the RPE toggle do?
It adds (10 − RPE) to your reps before the formulas run. A set of 5 at RPE 8 is treated as 7 effective reps, because you judged that about two reps were left. This is a simple reps-in-reserve adjustment, not the full Reactive Training Systems chart. That chart is on the RPE calculator.
Can I estimate a squat or deadlift here?
Yes. Open the Legs tab for back squat and front squat, or the Back tab for conventional, sumo, and trap-bar deadlift. Those choices stay on this page. Squat and deadlift notes are farther down the page if you want the context first.
How do dumbbell lifts work?
Enter the weight of one dumbbell. The estimate is for one dumbbell. Two 30 kg dumbbells are not a 60 kg barbell bench, and the calculator will not add them together.
What do I enter for weighted pull-ups, chin-ups, and dips?
Enter the added weight only, not your body weight. If you also type a body weight, the page shows a second line that adds it to the estimated added-weight max. That second line is a rough system total, not a separate formula.
Does the percentage chart use my estimated max?
Yes. 100% is the estimate on screen. Lower rows are that number times the percent, rounded to the plate increment you pick (2.5 kg or 5 lb by default, or the smaller plate option). The reps column is the inverse of the formula you selected.
Will my numbers be saved?
Only in this browser, if you press Log. History is local storage on your device. OneRepMax has no account and does not receive the weights you type.
Which unit does the page start in?
Pounds if your browser language looks like a US locale, kilograms otherwise. The choice is remembered on this device after you toggle it. The canonical page URL does not change with the unit.
Is the bench press calculator a different tool?
It uses the same math, preset to the bench press, with incline, decline, close-grip, and dumbbell variations and a bench percentage chart. Use it when the bench is the whole question. Use this page for every other lift.
Are these numbers medical or coaching advice?
No. They are arithmetic on the load and reps you typed. They do not know your joints, your training age, or whether the reps were strict. A spotter or safety arms still matter if you test a heavy single.
Who writes OneRepMax?
Jacob Young edits the site. The byline is an editorial credit. It is not a medical review and it is not a coaching certification. Corrections go to support@onerepmax.io.
Do you sell a program or store a training log?
No. The calculators are free and there is nothing to buy. A training-log product is not connected. History stays in your browser.