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Try our free One Rep Max Calculator for instant results.
Open Calculator โOverview
Structured strength training prescribes work sets as percentages of your 1-rep max. Knowing your 1RM lets you train with precision.
The Formula
1RM = Weight ร (1 + Repsรท30) | 90% for strength | 75-85% for hypertrophy
Standard formula used by professionals worldwide
Worked Example
Step-by-step
1RM = 100kg โ Strength sets: 90kg ร 3 reps | Hypertrophy: 77kg ร 8-12 reps
Key Concepts
- Accuracy: Results are as accurate as the inputs you provide
- Units: Always use consistent units throughout your calculation
- Verification: Double-check important calculations before making decisions
- Professional advice: For major financial, health, or structural decisions, consult a qualified professional
Privacy and Security
- All calculations run entirely in your browser
- No data is sent to any server
- No sign-up or personal information required
- Your data stays private โ always
Frequently Asked Questions
How often to test?
Every 4-8 weeks. More frequent interferes with training and risks injury.
What is progressive overload?
Gradually increasing weight, reps, or sets โ the fundamental driver of strength gains.
Train to failure?
Occasionally useful but consistently training close to failure impairs recovery.