The Util Box

1RM Calculator

Free online 1rm calculator. One rep max estimation. Track your health in your browser.

Epley
116.7 kg
w × (1 + r/30)
Brzycki
112.5 kg
w × 36 / (37 - r)
Lombardi
117.5 kg
w × r^0.1
Average 1RM
115.5 kg
254.7 lbs
Strength Level
Advanced
Training Percentages
% 1RMWeight (kg)Weight (lbs)Rep Range
65%75.1165.610–15
75%86.7191.06–10
85%98.2216.53–6
90%104.0229.32–4

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Copy and paste the code below into your website to embed this tool for free. An attribution link to The Util Box is required.

<iframe src="https://www.theutilbox.org/embed/one-rep-max-calculator" width="600" height="500" frameborder="0" style="border: none; max-width: 100%;" title="Free 1RM Calculator tool from The Util Box"></iframe>
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<a href="https://www.theutilbox.org/tools/one-rep-max-calculator">1RM Calculator by The Util Box</a>

Frequently Asked Questions about 1RM Calculator

What Is 1RM Calculator?

Free online 1rm calculator. One rep max estimation. Track your health in your browser. Whether you need a quick calculation, text transformation, or data conversion, this free online health fitness tool delivers instant results entirely in your browser — no server uploads, no sign-ups, and no data leaves your device.

How to Use the Free 1RM Calculator Online

  1. Enter your input — type, paste, or select data in the provided field.
  2. Adjust options — tweak any available settings or parameters to match your needs.
  3. Get instant results — output appears immediately as you type or after clicking a button.
  4. Copy or export — use the copy button to grab the result for use elsewhere.

All processing happens client-side using JavaScript, so your information never leaves your computer. This free online health fitness tool requires no registration and works on any modern browser.

Why Choose Our Free 1RM Calculator Tool?

  • 100% free — no hidden premium tiers or usage limits.
  • Fully private — runs entirely in your browser; no data is sent to any server.
  • Instant & fast — results appear in milliseconds with zero load times.
  • Works offline — after the first load, the tool is available without an internet connection.
  • No sign-up — open the page and start using it immediately.

1RM Calculator — Quick Reference

Feature Details
Category health fitness
Processing 100% client-side (browser)
Privacy No data leaves your device
Cost Free — no sign-up required
Works Offline Yes (after first load)