Loading page
About this tool
Calculate your estimated one-rep max weight using scientific formulas. Track your fitness progress with multiple calculation methods.
One Rep Max Calculator estimates the heaviest weight you could lift for a single rep, using the weight and rep count from a set you have already completed. It runs the well-known Epley, Brzycki and Lombardi formulas so you can compare estimates instead of trusting one number, and it works for any lift — squat, bench, deadlift or overhead press.
Open One Rep Max Calculator on AltFTool — it loads instantly in your browser.
Enter the values you already know.
Fine-tune the options to match your scenario.
Read the result and use it in your planning or reporting.
Epley, Brzycki and Lombardi disagree slightly by rep range — seeing all three tells you how confident the estimate is.
Turn one working set into the training percentages your programme actually asks for.
Estimate from a set you already did, so you skip the injury risk and fatigue of testing a real single.
It is most accurate from sets of about 3–6 reps, usually within a few percent of a true max. Above roughly 10 reps the estimate drifts high, because endurance starts to matter more than pure strength.
Each formula was fitted to different lifters and rep ranges. Brzycki tends to read lower at high reps, Epley slightly higher, and Lombardi uses a power curve. Taking the middle of the three is a reasonable working figure.
Use a hard set taken close to failure at 3–6 reps. A set you stopped well short of failure will underestimate your max, and a very high-rep set will overestimate it.
No — estimate each lift separately. Rep strength varies by movement, so your bench and deadlift will not follow the same weight-to-rep relationship even at the same effort.
Add the One Rep Max Calculator widget to your blog or website — free, responsive, no signup. Just keep the “Widget by AltFTool” credit link visible.
<iframe src="https://www.altftool.com/embed/widget/one-rep-max-calculator"
title="One Rep Max Calculator — free AltFTool widget"
width="100%" height="640" style="border:0;border-radius:12px;overflow:hidden"
loading="lazy" referrerpolicy="no-referrer-when-downgrade" allow="clipboard-write"></iframe>
<p style="font-size:12px;margin:4px 0 0">Widget by <a href="https://www.altftool.com/tools/all/one-rep-max-calculator?utm_source=embed&utm_medium=widget" rel="nofollow">AltFTool — free online tools</a></p>