Explore the efficiency of our Percentage Error Calculator on examples.com, perfect for quickly determining the accuracy of measurements. This tool is essential for students checking lab results, professionals assessing data quality, or anyone needing to calculate measurement errors. Ensure precision and ease with every calculation.

How to Use Percentage Error Calculator

To use the Percentage Error Calculator, you can follow these steps:

  1. Input the Experimental Value: In the first input box, type in the experimental value you obtained from your measurement, experiment, or data collection.
  2. Input the Theoretical Value: In the second input box, enter the theoretical value, which is the value you expected or the standard value against which you are comparing your experimental result.
  3. View the Percentage Error: After entering both values, the calculator will automatically compute the percentage error and display it in the area below the input boxes. This is calculated using the formula:
    Percentage Error=(Experimental Value−Theoretical Value/Theoretical Value)×100
    In the example shown in the image, with an experimental value of 44 and a theoretical value of 36, the percentage error calculated is 22.22%.
  4. Clear Values (if necessary): If you need to perform another calculation, click the “Clear” button to reset the values in the input boxes and repeat the process with new values.

This tool is particularly useful for checking the accuracy of measurements in various scientific and practical applications, ensuring you can assess the reliability and precision of your data effectively.

How to Calculate Percentage Error

Calculating percentage error is a useful way to measure the accuracy of a measurement compared to an accepted or true value. Here’s how you can calculate percentage error step-by-step:

Steps to Calculate Percentage Error

  1. Identify the Experimental Value: This is the value you have measured or obtained from an experiment.
  2. Identify the Theoretical or True Value: This is the value that is known to be the accurate or standard reference value.
  3. Calculate the Difference: Subtract the theoretical value from the experimental value. This can be done as follows:
    Difference=Experimental Value−Theoretical Value
  4. Divide the Difference by the Theoretical Value: This step helps to normalize the difference based on the expected value, giving a sense of scale to the error.
    Normalized Difference=Difference/Theoretical Value
  5. Convert to Percentage: To express the error as a percentage, multiply the normalized difference by 100.
    Percentage Error=Normalized Difference×100
  6. Interpret the Result: The result gives you the percentage error. A positive value indicates that the experimental value is higher than the theoretical value, while a negative value indicates that the experimental value is lower.

Percentage Error Formula

The formula for calculating percentage error is essential for assessing the accuracy of a measurement relative to a known or accepted value. The percentage error quantifies the difference between an observed (experimental) value and a true or theoretical value as a percentage of the theoretical value. Here is the formula:

Percentage Error=(Experimental Value−Theoretical Value/Theoretical Value)×100


  • Experimental Value: This is the value measured or observed in the experiment.
  • Theoretical Value: Also known as the true or standard value, this is the value that is accepted as the correct value based on reference standards or authoritative sources.
  • Percentage Error: This is the result of the calculation, which tells you how much the experimental value deviates from the theoretical value as a percentage.

Examples of Percentage Error Calculator

Example 1: Chemistry Lab

  • Experimental Value: 24.5 grams
  • Theoretical Value: 25.0 grams
  • Percentage Error:(24.5−25.0/25.0)×100=−2.00%
  • Interpretation: The experimental result is 2.00% less than the theoretical value, indicating a slight underestimation.

Example 2: Physics Experiment

  • Experimental Value: 981 cm/s²
  • Theoretical Value: 980 cm/s² (acceleration due to gravity)
  • Percentage Error:(981−980/980)×100=0.10%
    Interpretation: The experimental result is 0.10% higher than the theoretical value, showing very close accuracy.

Example 3: Biology Measurement

  • Experimental Value: 150.0 cm
  • Theoretical Value: 148 cm (height of a plant)
  • Percentage Error:(150.0−148/148)×100=1.35%
    Interpretation: The measurement is 1.35% more than the expected height, which might be due to natural variation or measurement error.

Example 4: Engineering Measurement

  • Experimental Value: 102 meters
  • Theoretical Value: 100 meters (length of a section of a bridge)
  • Percentage Error:(102−100/100)×100=2.00%
    Interpretation: The measured length is 2.00% longer than the design specification, which could be significant in engineering terms.

Example 5: Economic Data

  • Experimental Value: $305 billion
  • Theoretical Value: $300 billion (estimated GDP)
  • Percentage Error:(305−300/300)×100=1.67%
    Interpretation: The actual GDP is 1.67% higher than the estimated GDP, indicating a positive variance in economic performance.

Can percentage error be more than 100%?

Yes, percentage error can exceed 100%. This occurs when the absolute difference between the experimental and theoretical values is greater than the theoretical value itself.

Is a higher or lower percentage error better?

A lower percentage error is typically better as it indicates that the experimental value is closer to the theoretical value, suggesting higher accuracy and reliability of the measurement.

How can I minimize percentage error in experiments?

To minimize percentage error, ensure accurate measurement techniques, calibrate equipment properly, use high-quality and appropriate tools, and repeat measurements to average out any errors.

What does a percentage error of 0% mean?

A percentage error of 0% means that the experimental value perfectly matches the theoretical value, indicating an ideal measurement with no deviation.

What kind of values can I input into a Percentage Error Calculator?

You can input any numerical values into a Percentage Error Calculator as long as they represent comparable quantities (e.g., mass, distance, volume, budget, etc.).

Does a negative percentage error indicate a problem?

A negative percentage error simply indicates that the experimental value is lower than the theoretical value. It does not necessarily indicate a problem unless such a deviation is unexpected or unacceptable based on the experiment’s requirements.

What are common causes of percentage error?

Common causes include instrument calibration errors, user error in reading measurements, environmental conditions affecting the measurements, and inherent variability in the sample or system being measured.

Can percentage error be used in financial analysis?

Yes, percentage error is often used in financial analysis to compare estimated financial figures, such as budget forecasts or economic projections, with actual figures, helping to gauge the accuracy of financial models and assumptions.