Strength Standards & 1RM (One Rep Max) Calculator
Estimate your One Rep Max (1RM) using the Epley and Brzycki formulas. Enter the weight you lifted and how many reps you performed.
How The One Rep Max (1RM) Calculator Works
This 1RM calculator uses two of the most popular strength formulas: the Epley formula and the Brzycki formula. Both estimate the maximum weight you can lift for a single repetition based on the weight and reps you performed.
The calculator is ideal for lifters who want to estimate their strength without performing a risky max attempt. It's commonly used for creating powerlifting programs, strength progression charts, and gym training plans.
All calculations are done directly in your browser. Nothing is saved, tracked, or uploaded—making this tool fast, safe, and private.
Frequently Asked Questions
What is a 1RM?
1RM (One Rep Max) is the maximum weight you can lift for a single repetition.
Is this calculator accurate?
It provides an estimate using proven strength formulas, but real 1RM can vary depending on fatigue, technique, and training level.
Can I use pounds instead of kilograms?
Yes. The formulas work with any weight unit. Results will be in the same unit you input.
Is my data stored?
No. Everything is calculated locally on your device.