1RM Lombardi Calculator

Lombardi 1RM: a conservative power-rule estimate

The Lombardi formula (1989) estimates the one-rep max from a submaximal set with a power function: 1RM = weight · reps^0.10. The linear formulas (Epley, Brzycki) climb steadily; here the 0.10 exponent grows slowly with reps, so Lombardi stays conservative on low-rep sets and drifts off reality less than the others when reps get very high. Example: 80 kg × 5 reps → 80 · 5^0.10 = 80 · 1.175 ≈ 94 kg. It's sharpest in the 1-5 reps range. Past 10 reps, fatigue and technique take over and every estimator (Lombardi among them) loses precision.

Applications: powerlifting and percentage-based training

It shows up when lifters prepare powerlifting meets (projecting opener, second and third attempts from training data), in percentage-based programs like Westside Conjugate and RTS that prescribe loads as %1RM, and in bodybuilding plans built off Greg Nuckols / Jim Wendler 5/3/1 variants. Coaches reach for Lombardi when an athlete reports more than 5 reps and they'd rather err on the low side.

FAQ

Why is Lombardi more conservative? The 0.10 exponent grows very slowly. At 10 reps it multiplies the weight by just 10^0.10 ≈ 1.26, where Epley would multiply by 1.33.

Up to how many reps does it work? Dependable from 1 to 10 reps. Past 12, every 1RM formula (Lombardi included) overestimates, so treat the number with care.

Does it work for any exercise? It's at its best on compound lifts (squat, bench, deadlift). On isolation work, technique and local fatigue throw the estimate off.

Should I retest my 1RM directly? Only if you've got the experience, a spotter and a proper warm-up. For most lifters, estimating from a 3-5 rep set is the safer route and accurate enough.