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One Rep Max (1RM) Calculator

Calculate your one rep max from a weight and rep count. Get percentage-based training recommendations.

Understanding 1 Rep Max

Your 1RM is the maximum weight you can lift for one rep with proper form. It's the basis for percentage-based training.

1RM Formulas

  • Epley: Weight × (1 + Reps/30)
  • Brzycki: Weight / (1.0278 - 0.0278 × Reps)
  • Lander: (100 × Weight) / (101.3 - 2.67123 × Reps)

Training by Percentage

  • 100% (1 rep): Max strength test
  • 85-95% (2-5 reps): Strength training
  • 70-85% (6-10 reps): Hypertrophy
  • 60-70% (12-15 reps): Muscular endurance

Training Applications

  • Progressive overload: Gradually increase weight or reps
  • Periodization: Vary intensity across training cycles
  • Tracking progress: Monitor strength gains over time

Safety Tips

  • Always warm up thoroughly before heavy lifts
  • Use a spotter for maximal attempts
  • Maintain proper form - never sacrifice technique for weight

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Frequently Asked Questions

What is 1RM?

One Rep Max - the maximum weight you can lift for a single repetition. It's used to program training intensity.

How accurate are 1RM formulas?

Most accurate for 1-10 reps. Accuracy decreases with higher reps. Best to test actual 1RM periodically.

Which 1RM formula is best?

Epley and Brzycki are most commonly used. They give similar results for low reps. Use the average for best estimate.

How often should I test 1RM?

Every 4-8 weeks for serious lifters. Always warm up thoroughly and have a spotter for safety.