Leg Press Max Calculator (Estimated 1RM)

This calculator estimates the most you could leg press once (your one-rep max) from a set you actually did. Enter the weight and the number of clean reps; you get the Epley and Brzycki estimates and their average.

Formula

Epley: 1RM = w × (1 + r ÷ 30). Brzycki: 1RM = w × 36 ÷ (37 − r). Both turn a multi-rep set into an estimated single-rep maximum.

w: weight on the sled (kg works the same as lb)
r: reps completed with good form

Worked Example

200 lb for 8 reps.

Epley: 200 × (1 + 8 ÷ 30) = 200 × 1.26667 = 253.3 lb
Brzycki: 200 × 36 ÷ 29 = 248.3 lb
Average: (253.3 + 248.3) ÷ 2 = 250.8 lb

Limits and common mistakes

Estimates are best from sets of 2-10 reps; above 12 reps they drift apart, so the calculator accepts 1 to 12 reps.
Leg press numbers depend on the machine (sled angle, sled weight), so compare only on the same machine.
The estimate is for planning training loads; testing a true max should be done with care and a spotter.

Formula used

in w | Weight pressed | lb | 200 | 0 | 5000
in r | Reps completed | reps | 8 | 1 | 12
out ep | Epley estimate | lb | w * (1 + r / 30) | 1
out b | Brzycki estimate | lb | w * 36 / (37 - r) | 1
out avg | Average of the two | lb | (ep + b) / 2 | 1

Each line is one input (in, sel, list) or one result (out: label, unit, formula, decimals). How the calculators work

Photo collage: a leg press machine with weight plates in an empty gym. — Save this card: a 1000 × 1500 image of Leg Press Max Calculator (Estimated 1RM).

Method: the standard formula for this calculation, rounded as each result states. See how the calculators work or report an error.

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