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Estimate 1RM using Epley formula with strength chart.
One Rep Max Calculator is a free browser-based tool that helps you estimate 1rm using epley formula with strength chart. It is part of ToolsMonk's medical tools collection, so you can finish the job without downloading software, creating an account, or jumping between multiple websites.
This tool is especially useful for workflows such as estimating your max lift without attempting a risky true max, programming working weights as percentages of 1rm, and tracking strength progress over time. Because it runs directly in your browser, you can use it on desktop, tablet, or mobile while keeping the process fast and easy for one-off tasks as well as repeat work.
One Rep Max Calculator is designed for people who want a practical, privacy-friendly workflow with instant results inside the larger ToolsMonk library.
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
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 powerful free online tool available on ToolsMonk that helps you estimate 1rm using epley formula with strength chart. Whether you're a professional, student, or casual user, our one rep max calculator 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 happens client-side, ensuring your data remains completely private and secure. 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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