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One Rep Max Calculator

The One Rep Max Calculator estimates the most weight you could lift for a single rep (1RM) from a set you’ve done, using the Epley and Brzycki formulas. It also gives a percentage table of working weights for different rep targets.

Beginner⏱ 30 secondsUpdated 2026-07-09
Estimated one-rep max
212lb
Epley 216 · Brzycki 208 lb

Training weights by rep target

212 lb
1 rep · 100%
201 lb
2 reps · 95%
197 lb
3 reps · 93%
191 lb
4 reps · 90%
184 lb
5 reps · 87%
180 lb
6 reps · 85%
170 lb
8 reps · 80%
159 lb
10 reps · 75%
142 lb
12 reps · 67%

Averages the Epley and Brzycki formulas — reliable estimates for about 1–10 reps. The percentage table helps you pick working weights. Warm up, use a spotter, and never test a true 1RM without proper preparation. Estimates only.

How This Tool Works

Enter the weight you lifted and how many reps you completed. You’ll get your estimated 1RM plus a table of training weights for common rep targets (from 1 up to 12 reps).

Formula & Method

Epley: 1RM = weight × (1 + reps ÷ 30). Brzycki: 1RM = weight × 36 ÷ (37 − reps). The calculator averages the two, which are most accurate in the 1–10 rep range.

Example Calculation

If you bench 185 lb for 5 reps, your estimated 1RM is about 213 lb — so roughly 160 lb would be a 10-rep working weight (75%).

Please note: This calculator provides general estimates only and is not medical advice. It cannot account for your full medical history or individual circumstances — consult a doctor or qualified healthcare provider for guidance specific to you.

Frequently Asked Questions

How accurate is a 1RM estimate?+

Very reliable when your set was in the 1–10 rep range. Beyond about 10 reps the estimate drifts, since strength and endurance diverge.

Should I actually test my true 1RM?+

Only with proper warm-up, technique, and ideally a spotter. Estimating from a submaximal set (like this tool does) is much safer for most lifters.

What are the percentages for?+

They’re common training loads — e.g. ~85% for 5 reps, ~75% for 10 — so you can program working sets from your estimated max.

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<a href="https://everyfix.net/tools/one-rep-max-calculator/">One Rep Max Calculator</a> by <a href="https://everyfix.net">EveryFix</a>

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