507 lb works out to 5x45 + 1x5 per side plus the bar — call it 505 lb in practice, since gyms rarely stock the odd change. At 8 reps the formulas are starting to drift apart — 31 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 405 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. 486 to 517 lb is a 6.1% 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, 507 lb, is a compromise between two genuinely different claims rather than a consensus.
Training loads from a 507 lb max
Programmes are written as percentages of the max, not as absolute weights. From 507 lb, rounded to the nearest 5 lb:
| Percentage | Load | Typical set |
|---|---|---|
| 95% | 480 lb | Heavy single |
| 90% | 455 lb | Doubles and triples |
| 85% | 430 lb | Sets of four to five |
| 80% | 405 lb | Sets of six |
| 75% | 380 lb | Sets of eight |
| 70% | 355 lb | Volume work, ten or more |
507 lb is 5x45 + 1x5 per side plus the bar, 505 lb loaded. At this load the 31 lb the formulas disagree by is bigger than a pair of 10s, which is a good argument for programming off the lower estimate — 486 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 405 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 507 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 507 lb. This is a training estimate, not medical advice.