How to Use the One-Rep Max (1RM) & Strength Calculator
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1
Select your weight unit: Kilograms (kg) or Pounds (lbs).
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2
Enter the weight lifted on a submaximal set (e.g., Bench Press, Squat, Deadlift, Overhead Press).
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3
Enter the number of completed repetitions performed with good form (1 to 12 reps).
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4
Review your estimated One-Rep Max across multiple validated strength formulas (Epley, Brzycki, Lander, Lombardi, O'Conner).
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5
Examine the Training Load Percentage Table (50% to 95% of 1RM) to plan power, hypertrophy, and strength cycles.
Practical Example & Use Case
Common Real-World Scenario
Lifting 100 kg for 5 clean reps on bench press yields an estimated 1RM of 116 kg, allowing you to accurately program 80% working sets at 93 kg.
Technical Notes & Limitations
Browser Engine Architecture
Formulas are most accurate when input repetitions are between 2 and 8 reps. Accuracy diminishes above 10 reps due to muscle endurance bias.
Frequently Asked Questions
Which 1RM formula is most accurate?
The Epley and Brzycki equations are the gold standards in exercise science literature, generally within 2-3% of actual tested 1RM for compound barbell lifts.