Lombardi One Rep Max Calculator

The Lombardi formula

1RM = w × reps^0.10, where w is the weight lifted and reps the number completed. Best suited to any rep count, conservative.

Worked example

Deadlift 100 kg for 10 reps. Lombardi: 100 × 10^0.10 = 100 × 1.259 = 125.9 kg. For 100 kg × 5: 100 × 5^0.10 = 117.5 kg.

How it compares

Lombardi is one of the more conservative estimates. At 10 reps it gives about 126 kg where Epley gives 133 and Wathan 135. Because it is a smooth power function with no denominator, it never becomes undefined, which makes it a safe default when you only have a high-rep set to work from.

Which formula for which rep range

Rule of thumb: Brzycki, Lander and O'Conner for sets of 10 reps or fewer; Wathan and Mayhew when the set ran longer; Lombardi as a conservative all-rounder. The safest input is a hard set of 3 to 6 reps, where every formula nearly agrees.

The other 1RM formulas

• Epley formula — the default, and the parent calculator.
• Brzycki — 1RM = weight × 36 ÷ (37 − reps). The other standard; the most accurate of the set at low reps.
• O'Conner — 1RM = weight × (1 + 0.025 × reps). The gentlest estimate — 2.5% added per rep.
• Wathan — 1RM = 100w ÷ (48.8 + 53.8 × e^(−0.075 × reps)). An exponential fit that holds up well at higher reps.
• Lander — 1RM = 100w ÷ (101.3 − 2.67123 × reps). Close to Brzycki in shape; undefined near 38 reps.
• Mayhew — 1RM = 100w ÷ (52.2 + 41.9 × e^(−0.055 × reps)). Derived from bench-press data; a solid pick for higher reps.

Using the number

Once you have a 1RM, programmes prescribe work as a percentage of it — use the table above the fold to plan a session. Feed your bodyweight and goal into the calorie calculator and macro calculator to support the training, and see progressive overload for adding weight over time.

Source: Lombardi, 1989; see Wikipedia, "One-repetition maximum".