1RM Calculator

Calculate Your One Rep Max for Better Strength Training

Your Estimated 1RM

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What is a One Rep Max (1RM)?

A One Rep Max (1RM) is the maximum amount of weight you can lift for a single repetition of a given exercise with proper form. It's a crucial metric in strength training that helps determine your current strength level and plan your workout intensity.

Our 1RM calculator uses scientifically proven formulas to estimate your maximum lifting capacity based on submaximal lifts. This approach is safer than attempting a true maximum lift and provides accurate results for training purposes.

Key Features of Our 1RM Calculator

Multiple Formulas

Choose from 6 different scientifically validated formulas including Epley, Brzycki, and Lombardi for the most accurate results.

Easy to Use

Simply enter your weight lifted and repetitions performed, select a formula, and get instant results.

Safe Alternative

Calculate your 1RM without the risks associated with attempting maximum lifts in the gym.

Training Planning

Use your 1RM to calculate training percentages for different rep ranges and workout intensities.

How to Use the 1RM Calculator

Using our 1RM calculator is straightforward and takes just a few simple steps:

  1. Enter the Weight: Input the maximum weight you lifted in your recent set (in pounds or kilograms).
  2. Enter Repetitions: Specify how many repetitions you completed with that weight (ideally between 1-10 reps for accuracy).
  3. Choose Formula: Select your preferred calculation method. The Epley formula is most commonly used and recommended.
  4. Calculate: Click the calculate button to get your estimated 1RM instantly.

Benefits of Knowing Your 1RM

  • Workout Programming: Design effective training programs based on percentage-based loading
  • Progress Tracking: Monitor strength gains over time with objective measurements
  • Goal Setting: Set realistic and achievable strength targets for motivation
  • Competition Preparation: Plan attempt selection for powerlifting or weightlifting competitions
  • Injury Prevention: Avoid overloading by understanding your current capabilities
  • Training Specificity: Tailor your workouts to specific strength and power adaptations

Understanding the Different Formulas

Our calculator includes multiple formulas because different equations may be more accurate for different individuals and rep ranges:

Epley Formula

Most widely used formula, particularly accurate for rep ranges of 2-10. Formula: 1RM = Weight × (1 + Reps/30)

Brzycki Formula

Developed for use with rep ranges up to 10. Generally provides conservative estimates. Formula: 1RM = Weight ÷ (1.0278 - 0.0278 × Reps)

Lombardi Formula

Good for lower rep ranges (1-5). Uses an exponential calculation method. Formula: 1RM = Weight × Reps^0.1

Important Safety Considerations

While our 1RM calculator provides reliable estimates, remember these important safety guidelines:

  • Always warm up properly before testing submaximal loads
  • Use proper form and technique throughout your lifts
  • Have a spotter when lifting heavy weights
  • Test your 1RM estimates gradually rather than jumping to maximum weights
  • Consider your training experience and current fitness level
  • Allow adequate recovery between maximum effort sessions

Remember that these calculations provide estimates based on mathematical formulas. Individual variations in muscle fiber types, training experience, and technique can affect actual 1RM values. Use these results as a starting point for your training programs and adjust based on your actual performance.