About OneRepMaxCalc
Welcome to OneRepMaxCalc (onerepmaxcalc.net), a free online toolkit for lifters, coaches and anyone who wants to train smarter. Our main tool is a one rep max (1RM) calculator that estimates your maximum strength from a lighter, safer set, so you do not have to test a true max every time you want to plan your training.
What we offer
- 1RM estimates for 26 exercises, including bench press, squat, deadlift, overhead press, rows, pull-ups, dips and machine lifts.
- Seven established formulas (Epley, Brzycki, Wathen, Mayhew, Lombardi, Landers and O’Conner) shown side by side so you can see how estimates compare.
- RPE / reps-in-reserve adjustment for sets that were stopped before failure.
- Warm-up sets, percentage tables and a visual plate loader so you know exactly what to put on the bar.
- Strength standards that compare your estimated 1RM with your bodyweight.
Our mission
Strength training should be accessible, safe and based on sound numbers. We aim to give you clear, fast and free tools without sign-ups, and to explain the maths behind them in plain language.
How the calculator works
A 1RM calculator uses the relationship between the weight you lift and the number of repetitions you can complete to estimate the heaviest single repetition you could perform. All calculations run directly in your browser. Different formulas fit different movements and rep ranges, which is why we show several and highlight the one best suited to the exercise you choose.
Accuracy and responsibility
Every estimate is a prediction, not a guarantee. Individual results vary with technique, experience, fatigue and many other factors. Please read our Disclaimer and always train within your own limits.
Get in touch
We welcome feedback, bug reports and suggestions for new features. Visit our Contact page or email us at generalrustofficial@gmail.com.