Calculate your estimated leg press one-rep max from weight lifted and repetitions, or find the missing weight, reps, or max in lb, kg, g, or N.
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Leg Press Max Formula
The calculator uses the Epley one-rep max estimate. It estimates your leg press max from the weight you lifted and the number of repetitions you completed.
1RM = W * (1 + R/30)
- 1RM = estimated one-rep max
- W = weight lifted
- R = repetitions performed
If you enter weight lifted and repetitions, the calculator solves for estimated max:
1RM = W * (1 + R/30)
If you enter estimated max and repetitions, the calculator solves for the weight lifted:
W = 1RM / (1 + R/30)
If you enter weight lifted and estimated max, the calculator solves for repetitions:
R = 30 * (1RM/W - 1)
The weight fields can use pounds, kilograms, grams, or newtons. The calculation converts weight values to a common base unit first, then converts the answer back to the unit you selected.
Leg Press Max Reference Tables
Rep max estimates become less precise as reps get higher. Lower-rep sets usually give a better estimate of true maximum strength.
| Reps Performed | Multiplier Used | Estimated Max From 500 lb |
|---|---|---|
| 1 | 1.033 | 516.67 lb |
| 3 | 1.100 | 550.00 lb |
| 5 | 1.167 | 583.33 lb |
| 8 | 1.267 | 633.33 lb |
| 10 | 1.333 | 666.67 lb |
| Unit | Meaning | Approximate Conversion |
|---|---|---|
| lb | Pounds | 1 lb = 0.453592 kg |
| kg | Kilograms | 1 kg = 2.20462 lb |
| g | Grams | 1000 g = 1 kg |
| N | Newtons | 1 kg-force ≈ 9.80665 N |
Examples
Example 1: Estimate leg press max
You leg press 500 lb for 8 reps.
1RM = 500 * (1 + 8/30)
1RM = 633.33 lb
Your estimated leg press max is 633.33 lb.
Example 2: Find the working weight
Your estimated max is 600 lb, and you want to know what weight matches 5 reps.
W = 600 / (1 + 5/30)
W = 514.29 lb
The estimated 5-rep weight is 514.29 lb.
FAQ
Is a leg press max the same as a squat max?
No. A leg press max is usually much higher than a squat max because the machine supports your body and guides the path of movement. Do not use a leg press max to estimate a barbell squat max directly.
How accurate is the leg press max estimate?
It is an estimate, not a guaranteed true max. It is usually more useful when your rep count is low, such as 3 to 8 reps. Very high-rep sets can make the estimate less reliable because endurance becomes a bigger factor.
Should you test a true one-rep max on the leg press?
You can, but it should be done carefully. Use a full warm-up, set the safety stops correctly, and avoid testing a max if your form changes or your range of motion becomes shorter. An estimated max is often safer for tracking progress.
