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One Rep Max Calculator

Calculate your one-rep max from submaximal lifts using Epley and Brzycki formulas. See a full percentage chart for programming.

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Your Lift

Estimated One Rep Max

Epley Formula

215.8 lb

Brzycki Formula

208.1 lb

Percentage Chart (Epley)

100%
215.8 lb
1 rep
95%
205.0 lb
2 reps
90%
194.3 lb
4 reps
85%
183.5 lb
6 reps
80%
172.7 lb
8 reps
75%
161.9 lb
10 reps
70%
151.1 lb
12 reps
65%
140.3 lb
15 reps
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How to Use One Rep Max Calculator

  1. 1

    Enter weight lifted

    Enter the weight you lifted in pounds or kilograms.

  2. 2

    Enter reps

    Enter how many repetitions you completed.

  3. 3

    View 1RM

    See your estimated one-rep max using two proven formulas.

  4. 4

    Use percentage chart

    Reference the chart to plan your training weights.

Frequently Asked Questions

Your one-rep max is the maximum weight you can lift for a single repetition with proper form. It's used to program training percentages and track strength progress over time.

The Epley formula (1RM = weight * (1 + reps/30)) is most accurate for 10+ reps. The Brzycki formula (1RM = weight * 36/(37-reps)) is better for lower rep ranges (1-6). Both become less accurate above 10 reps.

Use 70-80% of 1RM for hypertrophy (8-12 reps), 80-90% for strength (3-6 reps), and 90-100% for maximal strength (1-3 reps). Most training programs use these percentages for progressive overload.

Testing a true 1RM carries injury risk, especially for beginners. Using submaximal estimates (like 3-5 reps) is safer and nearly as accurate. If you do test, use a spotter and proper warm-up.

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How One Rep Max Estimation Works

Directly testing your one-rep max is risky, especially for compound lifts like squats and deadlifts. Estimation formulas let you calculate your 1RM from a lighter set you can perform safely. The key insight: there is a predictable mathematical relationship between the weight you can lift and the number of repetitions you can complete. The fewer reps you can do, the closer that weight is to your true max.

Epley vs. Brzycki: Which to Trust

The Epley formula (1RM = weight x (1 + reps/30)) tends to overestimate at higher rep ranges. The Brzycki formula (1RM = weight x 36/(37 - reps)) is more conservative and considered more accurate for sets of 1-6 reps. Both formulas become unreliable above 10 reps because fatigue, technique breakdown, and muscular endurance increasingly influence performance. For the best estimate, use a heavy set of 3-5 reps.

Using Percentage Charts for Training

Once you know your 1RM, you can program training precisely. Strength programs typically use 80-95% of 1RM for 1-5 reps. Hypertrophy programs use 65-80% for 6-12 reps. Endurance work uses 50-65% for 15+ reps. Progressive overload — gradually increasing weight or reps over time — is the fundamental driver of strength gains. Recalculate your 1RM every 4-8 weeks to ensure your training percentages stay accurate as you get stronger.