Your one rep max (1RM) is the heaviest weight you can lift for a single repetition of an exercise. It is the standard benchmark for planning strength training. This free one rep max calculator uses the popular Epley formula to estimate your 1RM from a lighter set, and shows the common training percentages coaches use. Please treat the result as a general training estimate; it is not medical advice.
This is a general training estimate for information only and is not medical advice. Lift safely and consider using a spotter for heavy attempts.
How to Use
- Enter the weight you lifted in kilograms.
- Enter how many repetitions you performed with that weight.
- Select “Estimate 1RM” to see your estimated one rep max and training percentages.
Key Features
- Uses the widely used Epley formula.
- Shows useful training percentages from 60% to 100% of your max.
- Clearly labelled as a general estimate, not medical advice.
- Instant results with no sign-up required.
FAQs
What is a one rep max?
Your one rep max (1RM) is the maximum weight you can lift for one complete repetition of an exercise with good form.
How accurate is the Epley formula?
It is a well-regarded general estimate, most reliable for sets of 10 reps or fewer. Actual strength varies day to day.
Should I test my true 1RM?
True max testing carries injury risk. An estimated 1RM from a submaximal set is safer for most lifters, and this estimate is for guidance only, not medical advice.