Body Metrics Calc

Bench press calculator

Four equations, including one fitted on bench press data.

Units

The load on the bar for your set

Clean reps, close to failure. 2 to 10 is most reliable.

Your estimate

Enter your numbers. The estimate updates as you type.

Estimates, not medical advice.

Enter the weight on the bar and the number of reps you completed, and this calculator estimates the heaviest single you could bench. It runs four equations and shows all four, so you can see how much they disagree before you trust any of them.

This page is the bench-specific version. For other lifts and the full percentage chart, use the one-rep max calculator.

Why bench press gets its own page

The classic prediction equations were mostly fitted on bench press data, often from college students. Mayhew and colleagues' 1992 equation, for example, came from 435 college men and women performing the bench. A literature review posted as a preprint adds that these equations predict the bench better than they predict the deadlift, where all of them underestimated in a 1997 study.

That makes the bench the lift where an estimate is most likely to be close. It does not make it exact. Individual errors of around 10 percent turn up in the research, which on a 225 lb max is 22 lb.

The four equations

Weight is w and reps to failure is r.

Epley: w x (1 + r / 30).

Brzycki: w x 36 / (37 - r).

Lombardi: w x r^0.10.

Mayhew (bench specific): w / (0.522 + 0.419 x e^(-0.055 x r)). Use it for 2 to 10 reps only. At a single rep it returns about 109 percent of the weight lifted, because it is a fitted curve rather than a rule that must pass through 100 percent.

Worked example

You bench 185 lb for 8 reps, and the eighth was a grind.

Epley: 185 x (1 + 8/30) = 185 x 1.2667 = 234.3 lb.

Brzycki: 185 x 36 / 29 = 229.7 lb.

Lombardi: 185 x 8^0.10 = 185 x 1.2311 = 227.8 lb.

Mayhew: 185 / (0.522 + 0.419 x 0.6440) = 185 / 0.7918 = 233.6 lb.

The range is about 228 to 234 lb. That is tight, since 8 reps sits where the formulas agree. If the same 185 lb had been a set of 15, the spread would be far wider and none of the numbers would deserve much faith.

Getting a number you can use

Do the set early in the session, after a proper warm-up, with the same pause on the chest that you use in training. Stop the set when the next rep would fail or break form. Count only clean reps. Fatigue, poor sleep and a different bench or bar can move the result by a few pounds either way.

Lower reps are generally better for estimation. A set of 3 to 6 is a reasonable compromise between safety and accuracy, since you are far from the heaviest load you can move yet you are not dealing with the drift that sets in at higher reps. A study of 70 adults found that a 5-rep set predicted the bench max most closely, and accuracy declined at higher rep ranges, per a literature summary.

What the estimate is for

Programs written as a percentage of your max need a starting point, and the estimate is a sensible one. Re-run it every few weeks. If you hit a new rep record at the same weight, your estimated max has moved even if you never tried a single.

If you want to know your real max, do not attempt it from an estimate. Follow the steps in how to test your one-rep max safely: set up safeties, bring a spotter, and work up in stages.

About strength standards

Many bench calculators add a table that rates you as novice, intermediate or advanced by bodyweight. We have left that out. The tables we could find do not say where their numbers come from, or they rest on lifters submitting their own results. We could not find a freely citable source that we trusted enough to reproduce.

One peer-reviewed dataset does exist. It covers 809,986 entries from drug-tested, unequipped powerlifting competitions, published in the Journal of Science and Medicine in Sport in 2024. For lifters aged 18 to 35, the top tenth of competitors benched about 1.95 times bodyweight (men) and 1.35 times (women). Those are competitive powerlifters, so the figures describe an elite group and tell you nothing about what is typical for the general public. We read the abstract only, not the full percentile tables.

Who it does not suit

Anyone returning from a shoulder, chest or elbow injury, or with a heart or blood pressure condition, should get professional advice before working sets close to failure. People who bench with a heavy arch, a bounce or a very wide grip may find their rep pattern differs from the data the equations came from. And anyone who stops sets short of failure will see the estimate come out low.

Sources

  1. en.wikipedia.org: One repetition maximum
  2. arxiv.org: 2603.17495
  3. pmc.ncbi.nlm.nih.gov: PMC7367986
  4. pubmed.ncbi.nlm.nih.gov: van den Hoek et al. 2024

Questions people ask

How do I calculate my bench max from reps?

Pick a set close to failure of 2 to 10 reps, enter the weight and reps, and read the estimate. For example, 185 lb for 8 reps gives roughly 228 to 234 lb across four equations. The bench press calculator shows each one.

Is the bench estimate more reliable than for other lifts?

Somewhat. The classic equations were fitted largely on bench press data, and a 1997 comparison found bench predictions more reliable than deadlift predictions. Individual errors of 10 percent can still occur.

How many reps give the best estimate?

Fewer reps tend to work better. A study of 70 adults found a 5-rep set predicted bench max most accurately among 1, 5, 10 and 20 rep tests. Anything above about 10 reps makes the formulas disagree.

What is the Mayhew equation and why is it included?

It is a bench-specific equation from a 1992 study of 435 college students. We include it as a fourth opinion. It returns about 109 percent of the weight at a single rep, so use it only for 2 to 10 reps.

How much should I bench for my bodyweight?

We do not publish a table. The tables we found do not state where their numbers come from, or rely on self-reported results. The one peer-reviewed dataset we found describes competitive powerlifters: among drug-tested lifters aged 18 to 35, the 90th percentile bench was about 1.95 times bodyweight for men and 1.35 for women. That describes an elite group, not an average person.

Does a pause on the chest change the number?

It can, since a paused rep is harder than a touch-and-go one, so the same weight and rep count would mean a stronger lifter under looser rules. We found no data on how much the pause shifts the equations. Use the same style every time and compare like with like.

Do I need a spotter for the set I use?

For sets close to failure, yes, or use safety arms in a rack. The estimate does not require a miss, so stop at the last clean rep you are confident about.

How often should I recalculate?

Every few weeks, or when a rep PR at the same weight suggests it has changed. Day-to-day variation in tested 1RM is about 4 percent, so small shifts mean little.