73 lb works out to 1x10 + 1x5 per side plus the bar — call it 75 lb in practice, since gyms rarely stock the odd change. 4 reps sits comfortably inside the 2-to-10 range these formulas were fitted on, so this estimate is about as reliable as the method gets. Your 65 lb set represents about 89% of the estimated max.
How far 73 lb can be trusted
Four reps still sits in the well-behaved part of the range. The seven equations return 71 to 76 lb, and most of that 6.8% gap is them disagreeing about how fast strength falls off with reps rather than any of them being wrong. A set of four is also long enough that fatigue in the last rep is visible: if rep four was a grind, this estimate is honest; if it moved easily, 73 lb is on the low side.
Training loads from a 73 lb max
Programmes are written as percentages of the max, not as absolute weights. From 73 lb, to the nearest pound, because 5 lb steps collapse into each other at this load:
| Percentage | Load | Typical set |
|---|---|---|
| 95% | 69 lb | Heavy single |
| 90% | 66 lb | Doubles and triples |
| 85% | 62 lb | Sets of four to five |
| 80% | 58 lb | Sets of six |
| 75% | 55 lb | Sets of eight |
| 70% | 51 lb | Volume work, ten or more |
At this end of the rack almost none of those percentages lands on a plate you own. 73 lb itself builds as 1x10 + 1x5 per side plus the bar, which is 75 lb — near enough, and the miss is smaller than the 5 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 65 lb for 4 reps; the headline figure is their median. All seven assume a set taken close to failure with clean technique. At 4 reps you are inside the band they were fitted on, so the largest error here is not the equation but judging how close your set really was to failure — three reps left in the tank reads exactly the same to them. 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 73 lb. This is a training estimate, not medical advice.