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One Rep Max Calculator

Estimate your 1RM for strength training from reps + weight.

Privacy: All calculations will run locally in your browser. We do not send your inputs to any server.
Tip: your entries are never placed in the page URL.
Switching units will automatically convert values if the other fields are empty.
Use a weight you can lift with good form for 1–10 reps.
Best accuracy is usually between 1–10 reps.
Epley and Brzycki are the most commonly used. Lombardi tends to be higher at more reps.
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About One Rep Max

This page is a placeholder. Next, we’ll add the full set of inputs, formulas, and guidance—written in plain English.

How it will work

As you enter values, results will be calculated in your browser (no server calls). You’ll be able to export a summary and (optionally) store results locally as history.