Estimate your one-rep max (1RM) for any lift using seven scientifically validated formulas: Epley, Brzycki, Lander, Lombardi, Mayhew, O'Conner, and Wathan. View training zone percentages and compare formula results.
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Your one rep max is the maximum weight you can lift for a single repetition with proper form. It's used to set training percentages and track strength progress.
The Epley and Brzycki formulas are considered most accurate for reps under 10. For higher rep ranges (10+), the Wathan and Mayhew formulas tend to be more reliable. This calculator shows all seven for comparison.
Common training zones: 90-100% for maximal strength (1-3 reps), 75-85% for strength/hypertrophy (4-8 reps), 65-75% for hypertrophy (8-12 reps), and 50-65% for endurance (12+ reps).
Using the One Rep Max Calculator is simple: visit the tool page, enter your data or input into the provided fields, and get instant results. No downloads, installations, or sign-ups are required. The tool runs directly in your web browser for maximum convenience.
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The One Rep Max Calculator uses industry-standard formulas and algorithms to deliver reliable results. While the tool is designed for accuracy, results should be used as estimates and guidance. For critical decisions, always consult a qualified professional.
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Estimate your one-rep max (1RM) for any lift using seven scientifically validated formulas: Epley, Brzycki, Lander, Lombardi, Mayhew, O'Conner, and Wathan. View training zone percentages and compare formula results.
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Enter the weight you lifted and how many reps you completed to estimate your one rep max across 7 proven formulas.
One of the most widely used formulas. Works best for rep ranges of 1-10. Tends to overestimate at higher rep counts.
Very popular in academic and professional settings. Most accurate in the 1-10 rep range. Produces identical results to Epley at 10 reps.
A linear regression model. Provides consistent estimates across moderate rep ranges.
A power-law based formula. Tends to give more conservative estimates compared to other formulas.
Developed using collegiate football players. Uses an exponential model for a good fit across wider rep ranges.
A simple linear model. Generally provides the most conservative estimates and works well for low rep ranges.
An exponential model that tends to produce slightly higher estimates. Often used alongside Epley and Brzycki for comparison.