One Rep Max Calculator

- May 09, 2025
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Calculate your one-rep max (1RM) based on the weight you can lift for multiple repetitions. This calculator supports different formula methods for more accurate estimations.

Exercise Information

Weight & Reps

Advanced Options

About One Rep Max (1RM)

One Rep Max (1RM) is the maximum amount of weight you can lift for a single repetition of a given exercise. Directly testing your 1RM can be risky, which is why these formulas are used to estimate it safely from submaximal lifts.

Common Formulas
  • Brzycki: 1RM = Weight × (36 / (37 - Reps))
  • Epley: 1RM = Weight × (1 + 0.0333 × Reps)
  • Lander: 1RM = (100 × Weight) / (101.3 - 2.67123 × Reps)
  • Lombardi: 1RM = Weight × Reps0.1
  • Mayhew: 1RM = Weight / (0.522 + 0.419 × e(-0.055 × Reps))
  • O'Conner: 1RM = Weight × (1 + 0.025 × Reps)
  • Wathen: 1RM = Weight / (0.488 + 0.538 × e(-0.075 × Reps))
Tips for Accurate Estimation
  1. For best results, use reps in the 1-10 range
  2. Different formulas may be more accurate for different exercises
  3. Formula accuracy tends to decrease as reps increase
  4. Consider using the average of multiple formulas for better estimates
Training Applications
  • Use your 1RM to determine appropriate working weights for different rep ranges
  • Track changes in your 1RM over time to measure strength progress
  • Program strength cycles based on percentages of your 1RM
  • Set realistic strength goals based on your current 1RM

Understanding the One Rep Max Calculator

The One Rep Max (1RM) Calculator is a handy tool for anyone looking to improve their strength training. It estimates the maximum weight you can lift in one repetition of a given exercise. This calculator uses various formulas to provide accurate results based on the weight you can lift for multiple reps. Knowing your 1RM can help you set appropriate goals and track your progress over time.

How to Use the Calculator

This calculator is user-friendly and straightforward. You start by selecting the type of exercise, such as the bench press or squat. After that, you input the weight you've lifted and the number of repetitions performed. You can also choose how many decimal places you'd like the results to show. The calculator quickly gives you an estimate of your 1RM and can show results using different methods.

Advanced Options for Better Accuracy

For those who want a more tailored experience, the calculator offers advanced options. You can select from various calculation methods, including the Brzycki and Epley formulas. Each method has its strengths, so you might find one works better for you than others. Here are some features you can choose:

  • Select a calculation method from multiple options.
  • Choose how many decimal places to include in your results.
  • Decide whether you want to see estimates from all formulas.

Benefits of Calculating Your 1RM

Knowing your one-rep max can help in multiple ways. It allows you to set realistic training goals and adjust your weights accordingly. You can use your 1RM to determine the right weights for different training ranges, ensuring you challenge yourself without risking injury. Here are some benefits:

  • Identify appropriate working weights for specific rep ranges.
  • Monitor your strength progress over time.
  • Plan your strength cycles based on your 1RM.

Common Formulas Used in Calculations

The calculator includes several well-known formulas for estimating your 1RM. Each formula has slightly different calculations and may provide unique insights. Some of the most popular include:

  • Brzycki: 1RM = Weight × (36 / (37 - Reps))
  • Epley: 1RM = Weight × (1 + 0.0333 × Reps)
  • Lander: 1RM = (100 × Weight) / (101.3 - 2.67123 × Reps)

Practical Tips for Estimation

To get the best results from the 1RM Calculator, keep a few tips in mind. It's advisable to use repetitions in the range of 1 to 10 for more accurate estimates. Different exercises may yield better results with specific formulas. If you're unsure, consider averaging results from various methods to find a reliable estimate of your 1RM.

Tracking Your Progress

Keeping track of your estimated 1RM over time is essential for strength training. As you increase your lifting capacity, your 1RM will change, providing a clear snapshot of your progress. You can use this information to adjust your training plans and set new goals that reflect your growing strength.

Conclusion: The Value of Knowing Your 1RM

Using the One Rep Max Calculator is an excellent way to enhance your training routine. By knowing your 1RM, you can set goals, measure progress, and make informed decisions about your workout plans. Whether you're a beginner or an experienced lifter, this tool can help guide your strength training journey.