One Rep Max (1RM) Calculator
Estimate your maximum lifting weight for bench press, squat, and deadlift
Testing your true one-rep max can be dangerous without a spotter. This calculator estimates your 1RM based on a weight you can lift for multiple repetitions.
Calculator Inputs
lbs or kg (result matches input)
Max reps performed (1-10 is best)
Results
Enter values above to see your results
How It Works
We use proven formulas (Epley, Brzycki, etc.) that analyze the relationship between weight lifted and reps performed to project your max strength.
Tips & Best Practices
- •Estimates are most accurate for rep ranges between 3 and 10.
- •Above 10 reps, fatigue becomes a bigger factor than raw strength.
- •Use this to calculate percentages for your training program (e.g., 5 sets of 5 at 75% 1RM).
Frequently Asked Questions
Is this accurate for all exercises?
It is most accurate for compound lifts like Bench Press, Squat, and Deadlift. It is less accurate for isolation movements like curls.
Guides & Articles
Beyond BMI: The Truth About Body Composition in 2026
BMI is a useful screening tool, but it's not a diagnosis. We explore Body Fat %, TDEE, and the metrics that actually define metabolic health.
The Data-Driven Pregnancy: Understanding Due Dates and Fertility Windows
Conception and pregnancy are biological processes governed by timing. We explain the math of ovulation windows and the Naegele's Rule for due dates.
The Science of Energy Balance: TDEE, BMR, and Metabolism
Why do diets fail? Because they ignore the baseline data. Learn how to calculate your energy needs and manipulate them for weight loss or muscle gain.
Related Calculators
RPE Calculator
Estimate 1 Rep Max and working weights based on RPE (Rate of Perceived Exertion)
BMI Calculator
Calculate your Body Mass Index (BMI) and understand your weight status
BMR Calculator
Calculate your Basal Metabolic Rate (BMR) - the number of calories your body burns at rest
TDEE Calculator
Calculate your Total Daily Energy Expenditure (TDEE) - exactly how many calories you burn per day