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.
Rytell Tools publishes and maintains this calculator. It compares several published 1RM formulas, explains their assumptions, and provides context for the results. Estimates do not replace individual coaching or a safe lifting plan.
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.
This site is free to use. We may earn commissions from disclosed affiliate or referral links, and we may display advertising through Google AdSense when advertising is enabled. Commercial relationships do not change calculator formulas or results. See our Privacy Policy for information about third-party services and cookies.
Ryan Chow operates this site under the Rytell Tools brand. Ryan is the Phoenix-based founder of Rytell Digital Studio. Rytell Tools is the publishing brand for the calculators and guides on this site.
Our tools document calculation assumptions, and our guides link to reference sources. Results are estimates for planning and education. Any named contributor or professional reviewer receives a separate credit describing their role. You can check the linked sources and contact the publisher with questions about the method or a correction.
Send corrections, source questions, or privacy requests to rytellbiz@gmail.com or use the contact form. Include the page URL and the calculation or statement you want us to check.