About
The Rep Max Calculator is a free suite of gym tools for serious lifters — a one-rep max calculator using six proven formulas, a Wilks and DOTS score calculator, a warm-up set generator, and a visual plate loader. It's built for powerlifters, Olympic lifters, and dedicated gym-goers who want accurate numbers without the guesswork.
This site is built and maintained by the Rytell strength team — everyday lifters who program our own training around exactly these numbers. We're not a certification body and we don't pretend to be your coach: we're people who got tired of 1RM calculators that quietly used a single formula, never explained the difference between them, and offered no context for the result. So we built the tool we wanted, and we keep it current.
Because strength training is a health topic, we're deliberate about where our numbers come from and careful not to overstate what a calculator can tell you. The tool informs your planning; it does not replace a qualified coach, and it is not medical advice.
Every estimate is grounded in published, peer-reviewed work rather than invented rules of thumb. The 1RM calculator runs your input through six established equations — Epley, Brzycki, Lombardi, O'Conner, Wathan, and Mayhew — and reports their average, because each drifts in a different direction as reps rise. Our Wilks and DOTS scores use the official coefficient tables (the IPF adopted DOTS over Wilks for competition in 2020, so we report both). Strength standards reflect commonly-cited bodyweight ratios cross-referenced with competition data and resources from the National Strength and Conditioning Association (NSCA) and evidence-based sources like Stronger By Science. We explain this in more depth in our guides on 1RM formulas, strength standards, and Wilks vs DOTS.
The Rep Max Calculator is built and maintained by the Rytell strength team. It is free to use and always will be, and the site is supported by advertising through Google AdSense. You may see ads displayed on our pages, and we may also include occasional affiliate links to relevant equipment. As an Amazon Associate and affiliate partner, we may earn a small commission on qualifying purchases at no additional cost to you. This support keeps the tool free while we continue to research, verify, and update our content.