What Is My One-Rep Max if I Lift 455 lb for 8 Reps?

455 lb for 8 reps, run through all seven published formulas — median 569 lb, and the 35 lb they disagree by shown rather than hidden.

Estimated one-rep max569lb

median of seven formulas — the full range is 546 to 581 lb

Lowest of the seven 546 lb
Highest of the seven 581 lb
Your set was 80% of max

The set you actually did
lb
Units

The formulas are ratios, so the unit only changes the label — 225 kg for 5 works exactly like 225 lb for 5.

Every one-rep-max formula applied to this set
FormulaEquationEstimate
Brzycki 565 lb
O'Conner 546 lb
Lander 569 lb
Wathan 581 lb
Epley 576 lb
Lombardi 560 lb
Mayhew 575 lb

Fitted on sets of 2 to 10 reps. Above 10 the estimates drift apart and none of them is dependable.

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Last checked

569 lb works out to 5x45 + 1x35 per side plus the bar — call it 565 lb in practice, since gyms rarely stock the odd change. At 8 reps the formulas are starting to drift apart — 35 lb between the lowest and highest here — which is the method telling you the estimate is getting soft. Treat the lower end as the safer number. Your 455 lb set represents about 80% of the estimated max.

Why 8 reps widens the answer

Eight reps is where this method starts costing you accuracy. 546 to 581 lb is a 6.2% band, and a set of eight tests how long you can hold a brace as much as how much force you can produce. Wathan and Mayhew were built on bench-press data containing long sets and read high here; Brzycki reads low. The median, 569 lb, is a compromise between two genuinely different claims rather than a consensus.

Training loads from a 569 lb max

Programmes are written as percentages of the max, not as absolute weights. From 569 lb, rounded to the nearest 5 lb:

PercentageLoadTypical set
95%540 lbHeavy single
90%510 lbDoubles and triples
85%485 lbSets of four to five
80%455 lbSets of six
75%425 lbSets of eight
70%400 lbVolume work, ten or more

569 lb is 5x45 + 1x35 per side plus the bar, 565 lb loaded. At this load the 35 lb the formulas disagree by is bigger than a pair of 10s, which is a good argument for programming off the lower estimate — 546 lb — and letting the bar prove you wrong rather than the other way round. Warm-up jumps also get long here; work up in percentages rather than in fixed plate increments.

The formulas behind this answer, and their limitations

The table above the fold is Epley (1985), Brzycki (1993), Lombardi (1989), O'Conner (1989), Wathan (1994), Lander (1985) and Mayhew (1992), each applied to 455 lb for 8 reps; the headline figure is their median. All seven assume a set taken close to failure with clean technique. At 8 reps you are at the top of the band these equations were fitted on, and beyond it they diverge fast, so 569 lb is a ceiling rather than a target. They also under-rate strong, experienced lifters, who hold a higher percentage of max at any rep count than the regression average. The full account — the populations behind each equation, what a bounced rep does to it, and why we stop at ten reps — is set out on the methodology page. Warm up thoroughly and use safety bars or a spotter before going anywhere near 569 lb. This is a training estimate, not medical advice.

Common questions

455 lb for 8 reps is what one-rep max?

About 569 lb. The seven standard formulas range from 546 to 581 lb on these inputs, so the honest answer is “somewhere around 569”. In practice that is 5x45 + 1x35 per side plus the bar, or 565 lb loaded. Your 455 lb set is roughly 80% of that estimated max.

Why do the seven formulas disagree by 35 lb?

Each was fitted on a different group of lifters doing a different lift, so they curve differently as reps climb. At 8 reps that comes to 6.2%. Most calculators pick one of the seven silently; the spread is itself information about how much the number deserves to be trusted. All seven written out.

Should I try to lift 569 lb?

Not on the strength of an estimate from a 8-rep set, and not cold. From a set as long as 8 reps the estimate is at its least reliable, so treat 546 lb as the realistic target and 569 lb as optimistic. Make small jumps near the top, and set safety bars or use a spotter. If the point is to programme your training rather than to test, you do not need to attempt it at all — use the percentages above and adjust when your working sets start moving easily.