About Us
Built for lifters who want real numbers, fast
One Rep Max Calculator exists because most 1RM tools stop at a single number. You'd enter a weight and reps, get an estimate, and then have to do the rest of the math yourself — percentages for warm-ups, working sets, and comparisons across lifts. We built this tool to do all of that in one place, instantly, without reloading a page or juggling separate calculators for bench, squat, deadlift, and overhead press.
What we built
The calculator uses two well-established formulas — Epleyand Brzycki — so you can compare estimates side by side rather than trusting a single black-box number. Alongside your estimated max, you get a full rep-max chart (1 through 12+ reps) and a percentage-based training chart (50% to 100% of your max), both generated the moment you enter your numbers.
What we believe
Strength training tools should be fast, free, and honest about their limits. A one rep max calculator gives you a strong estimate, not a guarantee — we say so plainly throughout the site rather than presenting the number as more precise than it is. We also believe you shouldn't need an account, an app download, or your email address just to do some math before a training session, which is why the entire tool runs in your browser with no sign-up required.
How your data is handled
Your lift results are stored only in your own browser (via localStorage) so you can compare bench, squat, deadlift, and overhead press without re-entering numbers — nothing you type into the calculator is sent to us or stored on a server. See our Privacy Policy for the full details.