Lombardi Formula: Complete Guide

Lombardi formula 1RM notation card showing the equation one rep max equals weight times reps to the power of 0.10, developed by Victor Lombardi in 1989. Image title: Lombardi Formula 1RM Notation Reference Card

The Lombardi formula estimates your one-rep max using a power function rather than the additive scaling most other formulas use, which gives it a distinct behavior as reps rise: slightly above Epley at 1-5 reps, then progressively more conservative past 6. This guide covers the notation, worked examples, a full comparison against the other six formulas, the accuracy research, and when Lombardi’s output is the one worth trusting.

At a Glance

  • Formula: 1RM = w × r^0.10 (where w = weight, r = reps)
  • Type: Power function, grows more slowly than additive formulas
  • Behavior at 1-5 reps: Slightly higher than Epley; very close to Brzycki
  • Behavior at 6-10+ reps: Progressively more conservative than all additive formulas
  • Best used when: Input set is 6-10 reps and you want a conservative estimate
  • Developed by: Victor Lombardi (1989)

What is the Lombardi Formula?

The Lombardi formula estimates a lifter’s one-rep max by multiplying the weight lifted by the number of reps raised to the power of 0.10. Most other 1RM formulas use additive scaling, adding a fixed amount for each rep completed. Lombardi uses multiplicative scaling through a power function instead, producing a fundamentally different curve as reps climb.

The Notation and Plain English

Formula in notation:

1RM = w × r^0.10

Formula in plain English: multiply the weight you lifted by the number of reps you performed, raised to the power of 0.10.

Step by step:

  1. Count the exact number of clean reps completed (r)
  2. Raise r to the power of 0.10: calculate r^0.10
  3. Multiply by the weight used (w)
  4. The result is your estimated 1RM

Quick reference values for r^0.10:

Reps (r)r^0.10% above input weight
11.000+0%
31.116+11.6%
51.175+17.5%
81.231+23.1%
101.259+25.9%
121.282+28.2%

Why a Power Function?

A power function with an exponent of 0.10 grows slowly and bends downward: each additional rep adds progressively less than the one before it. Epley, by contrast, adds a fixed r/30 increment regardless of how many reps came before. The result is a smoother, more conservative curve at higher rep counts. Lombardi effectively assumes the strength-to-endurance ratio is less favorable at high reps than the additive models assume.

Who Developed the Lombardi Formula?

Victor Lombardi published this formula in 1989, part of the same generation of prediction research that produced Epley (1985) and Brzycki (1993), a period when strength coaches were trying to reduce reliance on dangerous maximum-effort testing. Lombardi’s contribution was structural: a power function instead of a linear factor, meant to produce more stable estimates across a wider rep range than the additive models available at the time.

Lombardi Formula: Worked Examples

Bench Press: 80 kg × 5 Reps

Calculation:

1RM = 80 × 5^0.10 = 80 × 1.175 = 94.0 kg

Your estimated bench press 1RM is 94.0 kg. To set your training weights, open the Percentage & Rep-Max Table in the calculator and enter 94 kg, which generates your full load chart automatically.

Comparison check: Epley at 80 kg × 5 reps gives 80 × (1 + 5/30) = 80 × 1.167 = 93.3 kg. Lombardi runs 0.7 kg higher than Epley at 5 reps, close enough that the two formulas agree in practice.

Squat: 120 kg × 8 Reps

Calculation:

1RM = 120 × 8^0.10 = 120 × 1.231 = 147.7 kg

Your estimated squat 1RM is 147.7 kg.

Comparison check: Epley at 120 kg × 8 reps gives 120 × (1 + 8/30) = 120 × 1.267 = 152.0 kg. Lombardi runs 4.3 kg lower than Epley at 8 reps. The gap grows with rep count: Lombardi is the more conservative the estimate, the higher you go.

Lombardi vs the Other 6 Formulas: The Full Comparison

Against Epley alone, Lombardi looks like a minor variation. Against all seven formulas at once, its behavior is distinctive: near the top of the pack at low reps, at the bottom by the time reps climb.

RepsLombardiEpleyBrzyckiLanderMayhewO’ConnerWathan
3111.6 kg110.0 kg108.1 kg111.5 kgN/A107.5 kgN/A
5117.5 kg116.7 kg116.3 kg116.7 kg115.1 kg112.5 kg116.8 kg
6119.6 kg120.0 kg120.0 kg119.4 kg118.2 kg115.0 kg119.8 kg
8123.1 kg126.7 kg127.3 kg124.8 kg124.1 kg120.0 kg125.8 kg
10125.9 kg133.3 kg133.3 kg130.2 kg128.1 kg125.0 kg131.6 kg
12128.2 kg140.0 kg140.0 kg135.7 kg133.8 kg130.0 kg137.5 kg

Bold marks where Lombardi leads the group (3-5 reps) versus where Epley and Brzycki pull ahead (6+ reps). Mayhew and Wathan show N/A at 3 reps due to formula constraints. Source: formula calculations using each equation in the calculator engine. Run all 7 formulas simultaneously for your own lifts using the one rep max calculator.

Line chart showing the crossover point between the Lombardi and Epley formulas at approximately 6 reps, with Lombardi running slightly higher than Epley from 1 to 5 reps and progressively more conservative than Epley from 6 reps onward.
Lombardi and Epley run almost identically through 5 reps, cross at 6, then diverge: by 12 reps Lombardi sits 11.8 kg below Epley on the same 100 kg input.

The Crossover Point: ~5-6 Reps

At 5 reps, Lombardi sits at 117.5 kg against Epley’s 116.7 kg, almost identical but slightly ahead. At 6 reps they cross: Lombardi drops to 119.6 kg, just under Epley’s 120.0 kg, and the gap widens with every rep after that. At 10 reps Lombardi runs 7.4 kg below Epley; at 12 reps, 11.8 kg below. This crossover is the defining trait of the power function, and it’s why Lombardi earns its keep for moderate-to-high rep sets rather than low-rep ones. See the Epley formula guide for the formula it’s crossing against.

How Accurate Is the Lombardi Formula?

LeSuer et al. (1997) is the only major validation study that tested Lombardi alongside the other formulas in this calculator. The honest finding: Lombardi performed moderately across all three competition lifts, tracking similarly to the others at low rep counts while showing less overestimation bias as reps rose. That conservative output at 6+ reps is simultaneously a strength (less likely to overestimate) and a weakness (may underestimate for fast-twitch-dominant athletes). The broader validation studies summarised in the research literature reach a similar conclusion.

Accuracy at a glance:

  • At 1-5 reps: comparable to Epley and Brzycki, within 1-2 kg for most inputs
  • At 6-10 reps: more accurate than Epley for lifters whose strength-endurance ratio sits below average
  • At 10+ reps: the most conservative formula in the engine, least likely to overestimate
  • Deadlift: like all seven formulas, underestimates the deadlift 1RM; add 5-10% to any deadlift output

For the broader accuracy picture across all seven formulas and every major lift, see How Accurate Are 1RM Calculators?

When to Use the Lombardi Formula

SituationUse Lombardi?Reason
Input set: 1-5 repsYes, among optionsAgrees closely with Epley; a slightly higher conservative baseline
Input set: 6-10 repsPreferredPower function models slower growth; less overestimation than additive formulas
Input set: 10+ repsBest choiceMost conservative formula; reduces risk of overestimated training loads
Competition attempt selectionCautionConservative estimates may undersell your true ceiling; use a direct test instead
Bench press estimationAcceptableMayhew is purpose-built for bench, but Lombardi works fine at 1-5 reps
High endurance-to-strength ratio lifterPreferredConservative output better matches this population’s actual 1RM
Beginner 8-10 rep estimationRecommendedSafer starting point; avoids overloaded training percentages

Use the one rep max calculator to see Lombardi’s output alongside all six other formulas at once, and let the NSCA’s published load percentages cross-check whatever training weight you land on.

Limitations of the Lombardi Formula

  • May underestimate for fast-twitch athletes. Lifters who generate high force in single-rep efforts relative to their multi-rep performance will consistently see Lombardi produce lower estimates than their actual 1RM.
  • No lift-specific calibration. Lombardi was built as a generalist equation, not calibrated separately for bench press, squat, or deadlift the way Mayhew was derived from bench data or Epley was validated specifically on squat.
  • Less familiar to coaches. Lombardi appears in fewer published programming resources than Epley, which can make its output harder to explain in a team or coaching setting.
  • Grows too slowly at very low reps. At 1-2 reps, Lombardi’s output runs slightly higher than the evidence suggests the true 1RM should be. Brzycki is the more conservative and better-supported choice at that extreme.

How to Use the Lombardi Formula With the Calculator

The one rep max calculator runs all seven formulas at once, Lombardi included. Enter your lift, weight, and reps, then check the Lombardi row. If it sits noticeably below the others, your input landed at a moderate-to-high rep count (6+), and Lombardi is doing exactly what it’s meant to: giving the most conservative estimate in the group, intentionally. The Percentage & Rep-Max Table then generates training loads from whichever formula’s output you program from. For a full side-by-side look, see All 1RM Formulas Compared.

Frequently Asked Questions

The Lombardi formula is 1RM = w × r^0.10, where w is the weight lifted and r is the number of reps completed. Multiply the weight by the number of reps raised to the power of 0.10. For example, 100 kg for 8 reps gives 1RM = 100 × 8^0.10 = 100 × 1.231 = 123.1 kg. The power function makes it more conservative at higher rep counts than additive formulas like Epley.

At 1-5 reps, Lombardi and Epley produce very similar results, within 1-2 kg of each other. The formulas cross at approximately 5-6 reps. Above that, Lombardi becomes progressively more conservative: at 10 reps from a 100 kg input, Lombardi predicts 125.9 kg while Epley predicts 133.3 kg, a 7.4 kg gap. Use Lombardi when your input set runs 6-10 reps and you want a conservative estimate; use Epley for a higher-end read on the same input.

Lombardi is the best choice when your estimation set uses 6 or more reps. Its power function grows more slowly than additive formulas, so it’s less likely to overestimate the true 1RM at moderate rep counts. It’s also a good pick for beginners using 8-10 rep estimation sets, since the conservative output helps avoid training percentages set too high. For 1-5 rep inputs, all seven formulas land close enough that the choice barely matters.

Victor Lombardi developed the formula and published it in 1989, during the same period of 1RM prediction research that produced Epley (1985) and Brzycki (1993). Lombardi’s approach, using a power function (r^0.10) instead of a linear additive factor, was designed to produce more stable estimates across a wider rep range than the formulas available at the time.

Like all seven formulas in the calculator, Lombardi underestimates the deadlift 1RM, a consistent finding across validation studies. No formula predicts the deadlift accurately, because near-maximal deadlift technique optimises differently from submaximal attempts. For the deadlift specifically, add 5-10% to the Lombardi output when setting competition openers or peaking targets. The formula is more reliable for bench press and squat.

Because it uses a power function (r^0.10) rather than an additive linear factor. An exponent of 0.10 grows very slowly, so each additional rep adds less to the predicted 1RM than it would under an additive formula. At 12 reps, Lombardi predicts 128 kg from a 100 kg input while Epley predicts 140 kg, an 11.8 kg gap from identical input data.

Yes. The one rep max calculator runs all seven formulas simultaneously, Epley, Brzycki, Lander, Lombardi, Mayhew, O’Conner, and Wathan, and displays every result. When Lombardi sits noticeably below the others, it signals a moderate-to-high rep input (6+), where its power function produces the most conservative estimate of the group.

The power function behind Lombardi makes it uniquely conservative at moderate-to-high rep counts, the right choice when you want an estimate that won’t overload your training percentages. It sits with Epley at 1-5 reps and pulls furthest below the group above 6. Run it alongside the other six rather than in isolation: a wide gap between Lombardi and Epley at your input rep count tells you something real about your strength-endurance profile. Start with 1RM Formulas & Calculations, compare it directly against Epley Formula: Complete Guide, or see the full field in All 1RM Formulas Compared.