One-Rep Max Calculator 2024

The free One-Rep Max Calculator to estimate your maximum strength and calculate optimal training percentages

One-Rep Max Calculator - Estimate Your Maximum Strength

Use our One-Rep Max Calculator to safely estimate your 1RM without maximal lifting. Enter the weight and reps you can perform with good form.

For best accuracy, use 1-10 reps with good form

Your One-Rep Max Results

Enter your lift data and click "Calculate" to see your estimated one-rep max.

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Enter your data

How to Use Our One-Rep Max Calculator

The One-Rep Max Calculator is designed to help you estimate your maximum strength without the risks of actual maximal lifting. Our One-Rep Max Calculator uses proven mathematical formulas:

One-Rep Max Calculator Safety Notice

Using our One-Rep Max Calculator is much safer than attempting maximal lifts, especially for beginners. Always prioritize proper form over heavier weights.

Step 1: Enter Your Lift Information

Select your exercise and enter the weight and number of repetitions you can complete with good form. For optimal accuracy, use a weight you can lift for 1-10 repetitions.

Step 2: Choose Your Calculation Formula

Our One-Rep Max Calculator offers multiple formulas to estimate your 1RM. Each formula may work better for different individuals and exercises. You can also select "Average" to use all formulas.

Step 3: Analyze Your Results

The One-Rep Max Calculator will display your estimated 1RM and provide a table of training percentages for program design. The chart compares results from different formulas for reference.

One-Rep Max Formulas Used in Our Calculator

Our One-Rep Max Calculator uses several scientifically validated formulas to estimate your maximum strength. Each formula has its own strengths and may work better for different individuals.

Brzycki Formula

1RM = Weight × (36 / (37 - Reps))

The Brzycki formula is one of the most widely used and tends to be more accurate for repetitions under 10. It works well for most compound exercises.

Epley Formula

1RM = Weight × (1 + 0.0333 × Reps)

The Epley formula is simple and reliable, especially for moderate rep ranges (3-10 reps). Many strength coaches prefer this formula for its consistency.

Lombardi Formula

1RM = Weight × Reps0.1

The Lombardi formula uses an exponential approach and may work better for experienced lifters. It tends to give slightly higher estimates than other formulas.

Mayhew Formula

1RM = Weight / (0.522 + 0.419 × e-0.055 × Reps)

The Mayhew formula uses an exponential decay function and may be more accurate for higher rep ranges (8-15 reps).

Want to Improve Your Strength?

Download our comprehensive strength training program designed to help you increase your one-rep max safely and effectively.

Using One-Rep Max in Your Training

Understanding your one-rep max is crucial for effective strength training program design. Here's how to apply your 1RM results:

Strength Training (1-5 reps)

  • Pure strength: 85-100% of 1RM
  • Typically 1-5 reps per set
  • Longer rest periods (3-5 minutes)
  • Focus on compound movements
  • Example: 5×3 at 85% 1RM

Hypertrophy Training (6-12 reps)

  • Muscle growth: 67-85% of 1RM
  • Typically 6-12 reps per set
  • Moderate rest periods (1-2 minutes)
  • Higher total volume
  • Example: 4×8 at 75% 1RM

Endurance Training (12+ reps)

  • Muscular endurance: 50-67% of 1RM
  • Typically 12-20 reps per set
  • Short rest periods (30-60 seconds)
  • Higher rep volume
  • Example: 3×15 at 60% 1RM

Scientific Background of One-Rep Max Calculation

One-rep max estimation formulas are based on exercise physiology research and have been validated in numerous studies.

IMPORTANT NOTICE

All 1RM calculations are estimates. Individual factors such as exercise technique, muscle fiber composition, and fatigue can affect actual maximum strength.

Research References

  • Brzycki, M. (1993). Strength testing: Predicting a one-rep max from reps to fatigue.
  • Epley, B. (1985). Poundage chart. Boyd Epley Workout.
  • Lombardi, V.P. (1989). Beginning weight training: The safe and effective way.
  • Mayhew, J.L., et al. (1992). Accuracy of prediction equations for determining one repetition maximum bench press in women before and after resistance training.

Accuracy Considerations

  • More accurate with lower rep ranges (1-5)
  • Less accurate with higher rep ranges (10+)
  • More accurate for compound exercises
  • Less accurate for isolation exercises
  • Individual variations can affect results

One-Rep Max Calculator Feedback and Community

We value your input to improve our One-Rep Max Calculator and help fellow strength enthusiasts train effectively.

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