ABOUT ONE REP MAX CALCULATORS
Know Your Numbers Train With Purpose
Practical tools and clear explanations for lifters who want to understand their strength—and put it to work.
01 / OUR PURPOSE
Why this site exists
Most percentage-based programs assume you already know your 1RM. They don’t tell you how to find it, how reliable the number is, or what to do when your calculator gives a different result from your training partner’s.
This site exists to close that gap. Use a set you’ve already done to get a working 1RM estimate across seven established formulas, a full percentage table, and a warm-up ramp.
No guesswork on what to put on the bar Tuesday.
Michael Swan
The lifter behind the tool
15
Years of training with barbells
01 / OUR PURPOSE
Built from time
under the bar
I’ve been training with barbells for 15 years, working through programs and paying close attention to how percentage-based loading actually behaves across training cycles.
My background is practical: commercial gyms and home setups, true maxes and estimated ones, and a lot of time understanding why the calculator number and the bar number don’t always agree.
I’m not a researcher or an academic. I don’t have a sports science degree. What I have is years of working through the same problems serious lifters face when programming off a number they’re not entirely sure is accurate.
Why I built this tool
The calculators I found were often cluttered, used a single unexplained formula, or gave you a number and stopped there. I wanted to see the spread across formulas and connect the estimate to useful training weights.
I built this to bring seven formulas, percentage and rep-max tables, a warm-up ramp, and an RPE reference together. The guides explain the rest—because knowing your 1RM is only useful if you know what to do with it.
03 / Tools & knowledge
From an estimate to a training plan
The Calculator
Enter your lift, weight, and completed reps. Compare seven estimates in one place, with a movement-specific formula default.
Percentage and rep-max table: 50–100%
Warm-up ramp for your working weight
RPE reference alongside your results
Epley · Brzycki · Lander · Lombardi
Mayhew · O’Conner · Wathan
The Guides
The reasoning a calculator can’t give you. Organized by topic for lifters who want to understand the numbers.
What a 1RM means and how formulas work
Formula limitations and safe testing
Strength standards relative to bodyweight
Programming around your estimate
Have feedback or a correction?
Share calculator feedback, guide corrections, or a topic you’d like us to cover through the contact form.