One Rep Max Calculator
One Rep Max Calculator
How it works: This calculator estimates your one-rep max (1RM) based on the weight you lifted and the number of reps you completed. Different formulas use different mathematical approaches to estimate 1RM. The training percentages show recommended weights for different intensity levels based on your estimated 1RM.
Overview
Estimate your one-rep max (1RM) using scientifically validated formulas based on weight lifted and reps completed. This calculator supports multiple estimation methods including Epley, Brzycki, Lander, Lombardi, Mayhew, O'Conner, and Wathan formulas. Get instant results showing your estimated 1RM plus training percentages for different intensity levels (60-95% of 1RM) with recommended rep ranges. Perfect for strength training, powerlifting, bodybuilding, or anyone looking to optimize their workout programming. The calculator provides visual charts and helps you plan progressive overload by showing appropriate weights for different training goals. All calculations happen instantly in your browser with complete privacy—no data is stored or transmitted.
About
About One Rep Max Calculator
Estimate your one-rep max (1RM) using multiple scientifically validated formulas and calculate training percentages.
Features:
- 7 different 1RM estimation formulas
- Training percentages from 60-95%
- Recommended rep ranges for each intensity
- Visual charts for strength planning
- Safe alternative to testing actual 1RM
- 100% client-side - your data stays private
FAQ
What is one-rep max (1RM)?
One-rep max is the maximum weight you can lift for one complete repetition of an exercise. It's used to determine training intensity and program strength workouts.
Which formula is most accurate?
Different formulas work better for different rep ranges. Epley is good for low reps, Brzycki for moderate reps. Most formulas are reasonably accurate within 5-10% for 2-10 reps.
Is it safe to test actual 1RM?
Testing actual 1RM carries injury risk, especially for beginners. Using estimation formulas is safer and provides reliable results for programming purposes.
How do I use training percentages?
Use percentages of your 1RM to set training weights. For strength: 85-95% (2-6 reps). For hypertrophy: 75-85% (6-12 reps). For endurance: 60-75% (15-20 reps).
Can I use this for any exercise?
Yes, but it's most accurate for compound exercises like squat, bench press, and deadlift. Isolation exercises may have different strength curves.