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Estimate 1RM using Epley formula with strength chart.
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One Rep Max Calculator is a free, browser-based tool built for one job: estimate 1rm using epley formula with strength chart. It is part of ToolsMonk's medical tools collection, so you can finish the work without downloading software, creating an account, or jumping between multiple websites.
Common scenarios include estimating your max lift without attempting a risky true max, programming working weights as percentages of 1rm, and tracking strength progress over time. The browser-based design means you can switch devices mid-task and pick up right where you left off, whether it's a one-time job or part of a daily workflow.
The design goal is simple: practical output on the first try, with a privacy-friendly workflow and the rest of the ToolsMonk library one click away.
| Price | Free, no signup, no paywall, no watermark |
|---|---|
| Works on | Any modern browser: desktop, tablet, and mobile |
| Processing | In your browser, files never leave your device |
| Account required | None |
| Category | Medical Tools |
Enter the weight you lifted and the number of reps
The tool estimates your 1RM using a strength formula
See common training percentages of that 1RM
Use it to set working weights
Estimates your one-rep max (1RM) from a weight and reps performed
Uses established strength formulas
Shows training percentages of your 1RM
Helps program lifts without testing a true max
Runs in your browser, your details stay on your device
Free, with no signup and nothing stored
Estimating your max lift without attempting a risky true max
Programming working weights as percentages of 1RM
Tracking strength progress over time
Setting training loads for a lifting program
One Rep Max Calculator is a free online tool on ToolsMonk with a single focus: estimate 1rm using epley formula with strength chart. Whether you're a professional, student, or casual user, it provides instant, accurate results right in your browser without requiring any software installation or account creation.
As part of our Medical Tools collection, this tool is designed with simplicity and power in mind. All processing runs locally in your browser, so your files and data never leave your device. The tool works seamlessly across all modern browsers on desktop, tablet, and mobile devices.
One-Rep Max Calculator estimates the most weight you could lift for a single rep, calculated from a weight you can do for several reps using validated formulas like Epley and Brzycki, without the injury risk of an actual max attempt.
Its great advantage is safety and repeatability. Testing a true 1RM is taxing and risky, especially solo, so estimating from a submaximal set is the standard approach, and it's exactly what strength programs rely on when they prescribe loads as percentages of 1RM rather than demanding frequent maximal tests.
Accuracy is best in lower rep ranges (roughly 2–6 reps); estimates drift as reps climb because high-rep performance reflects endurance as much as maximal strength. So for the truest figure, use a genuinely hard set at moderate reps, not a light high-rep set that overstates your max.
From the estimate, the displayed percentages let you program working weights for strength, hypertrophy, or endurance goals. It's informational, not training or medical advice, and your details never leave your browser. Pair it with the other ToolsMonk health and fitness calculators.
Estimate from a hard set of ~2–6 reps for accuracy; high-rep sets overstate strength
Use it to program working weights as %1RM rather than testing a risky true max often
Re-estimate periodically to track progress and update your training loads
Common questions about this tool, its workflow, and what to expect before you use it.
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Estimate 1RM using Epley formula with strength chart.
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