How to use

Select your exercise, enter the weight you lifted and how many reps you completed. The calculator instantly returns your estimated one rep max. Enable the RPE slider if you know how close to failure you were. This makes the estimate significantly more accurate for sub-maximal sets.

Below your result, you'll find a training percentage table with exact loads for every major zone, a 1–10 rep max breakdown, and a warm-up set planner building toward your target weight.

The 1RM Formula Explained

Several formulas exist to estimate one rep max from a sub-maximal set. They all use weight and reps as inputs

How to Use Your 1RM for Training

Your 1RM is a programming tool. Most strength and hypertrophy programmes prescribe intensity as a percentage of 1RM. Here's how percentages map to training goals:

• 50–60% — Warm-up, technique work, active recovery
• 65–75% — Hypertrophy (muscle building), 8–15 rep range
• 75–85% — Strength-endurance crossover, 5–8 reps
• 85–92% — Strength focus, 2–5 reps
• 93–100%+ — Near-maximal and maximal effort, 1–3 reps

The percentage table in the calculator shows exact loads for every 5% step — so you know exactly what to put on the bar.

1RM Calculator for Bench Press

Bench press is the most commonly tested 1RM lift. Select Bench Press in the calculator and enter your working set. A 3–5 rep set with a challenging weight gives the most accurate estimate. Avoid estimating from sets of more than 10 reps. Technique fatigue skews the result.

1RM Calculator for Squat

Squat 1RM calculations are most accurate in the 3–6 rep range. Because squats are highly technique-dependent, use a well-executed working set rather than a grinding near-failure set. Select Squat above and enter your best recent set.

1RM Calculator for Deadlift

The deadlift is the lift where grip fatigue and CNS fatigue appear earliest at higher rep counts. For the most accurate estimate, use a 1–5 rep set at high effort. Select Deadlift in the calculator for a deadlift-specific result.

RPE

RPE (Rate of Perceived Exertion) is a 1–10 scale measuring how close you were to failure. RPE 10 = no reps left. RPE 8 = approximately 2 reps remaining in the tank.

Without RPE, the calculator treats every set as a maximum effort. If you had 3 reps left, it will underestimate your true 1RM. The RPE slider adjusts the calculation to account for how hard the set actually was. This gives a meaningfully more accurate result for sub-maximal training sets.

Should You Test a True 1RM?

Not unless you are peaking for a competition or have a specific reason. True 1RM attempts carry a higher injury risk than sub-maximal training, require a spotter, and need a proper warm-up and peaking protocol. For day-to-day programming, a calculated 1RM is accurate enough.

If you do test a true max, use the warm-up planner in this calculator to ramp up safely without pre-fatiguing your central nervous system before the attempt.