One-Rep Max (1RM) Calculator: Epley & Brzycki Formulas
Estimate your one-rep max (1RM) for the bench press, squat, deadlift, or any lift using the Epley and Brzycki formulas, plus a training percentage chart from 50% to 100% of your max.
1RM Formulas (Epley & Brzycki)
Your one-rep max (1RM) is estimated from a weight you can lift for a known number of repetitions (ideally 1-10). This calculator averages two widely used prediction formulas — Epley and Brzycki — for a more reliable estimate, then generates a percentage chart for programming your training loads.
These formulas are most accurate for sets of 1-10 repetitions and become less reliable for higher rep ranges. For the safest and most accurate estimate, use a weight you can lift for 3-6 reps with good technique. Always warm up properly and use a spotter or safety equipment when testing heavy loads.
How to Use the 1RM Calculator
Choose your unit
Select kilograms (kg) or pounds (lb) to match the unit on your weights.
Enter the weight you lifted
Use the heaviest weight you recently lifted with good form for a known number of reps.
Enter the number of reps
Enter how many reps you completed with that weight, ideally between 1 and 10.
Click Calculate
See your estimated one-rep max and a percentage chart showing training loads from 50% to 100% of your 1RM.
Real-World Scenario Example
"A lifter benches 100 kg for 5 reps and wants to estimate their one-rep max."
Inputs
Result
Epley estimate ≈ 116.7 kg, Brzycki estimate ≈ 112.5 kg, averaging to an estimated 1RM of about 114.5 kg. At 80% of this 1RM, a training set would use about 91.5 kg.
Important Disclaimer
This calculator provides an estimate for informational and training-planning purposes only and is not a substitute for professional coaching. Estimated values may differ from your true one-rep max. Always warm up properly, use correct technique, and use spotters or safety equipment when lifting heavy weights.
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