153 lb works out to 1x45 + 1x10 per side plus the bar — call it 155 lb in practice, since gyms rarely stock the odd change. At 10 reps the formulas are starting to drift apart — 11 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 115 lb set represents about 75% of the estimated max.
Why 10 reps widens the answer
Ten reps is the last rep count with a page on this site, and it is the least reliable of them. All seven equations were fitted on sets of two to ten, so ten is the boundary itself; past it they diverge fast enough that we do not publish the pages at all. The 11 lb spread here — 7.2% — is the honest width of the answer. A ten-rep set measures endurance as much as strength, so if you want a number to programme from, repeat the test with four or five reps.
Training loads from a 153 lb max
Programmes are written as percentages of the max, not as absolute weights. From 153 lb, rounded to the nearest 5 lb:
| Percentage | Load | Typical set |
|---|---|---|
| 95% | 145 lb | Heavy single |
| 90% | 140 lb | Doubles and triples |
| 85% | 130 lb | Sets of four to five |
| 80% | 120 lb | Sets of six |
| 75% | 115 lb | Sets of eight |
| 70% | 105 lb | Volume work, ten or more |
At this end of the rack almost none of those percentages lands on a plate you own. 153 lb itself builds as 1x45 + 1x10 per side plus the bar, which is 155 lb — near enough, and the miss is smaller than the 11 lb the seven formulas disagree by. This is the weight range where a pair of 2.5 lb or 1.25 lb plates genuinely earns its place, because a 10 lb jump here is a much larger proportional step than it is at 300.
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 115 lb for 10 reps; the headline figure is their median. All seven assume a set taken close to failure with clean technique. At 10 reps you are at the top of the band these equations were fitted on, and beyond it they diverge fast, so 153 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 153 lb. This is a training estimate, not medical advice.