Percent Error Calculator

Values must be greater than equal to zero

Percent Error Calculator at Calculator Town

It is crucial to determine the precision of measurements and experimental data. Calculating the percent error is a common way of assessing a measurement's accuracy. This percent error calculator determines the relative error by comparing a measurement's observed value to its true value. With the help of this tool, you can quickly determine whether your measurement was accurate.

Fortunately, in this digital age, we have the convenience of online tools like the percent error calculator at Calculator Town, which simplifies the process of determining percent error. This guide will explore the concept of percent error, its significance, how to effectively use a percent error calculator, the percent error formula, and how to calculate percent error.

What is the Percent Error?

Before delving into the details of the Percent Error Calculator, it is important to grasp the concept of percent error itself. Percent error is a measure of the accuracy of a measurement, expressed as a percentage.

A positive percent error indicates that the measured value is greater than the accepted value, while a negative percent error suggests that the measured value is smaller. Ideally, a percent error of zero would imply a perfect measurement, meaning the measured value precisely matches the accepted value. However, in practical scenarios, a small percent error is considered acceptable, depending on the precision and nature of the measurement

Importance of Percent Error

Percent error plays a vital role in numerous fields, including science, engineering, and statistics, due to its significance in evaluating the accuracy and reliability of measurements and experimental data. This quantitative measure provides valuable insights and benefits in several ways.

1. Assessment of Accuracy: Percent error helps researchers determine the reliability of their results by comparing measurements to accepted values, providing a numerical representation of the deviation between the measured and ideal values.

2. Identification of Systematic Errors: Scientists can identify and analyze sources of systematic errors by calculating percent error, which serves as an indicator of consistent deviations from the true value caused by factors like calibration, measurement techniques, or experimental procedures.

3. Refinement of Measurement Techniques: Percent error aids in refining measurement techniques by pinpointing areas for improvement. By analyzing the magnitude and direction of the percent error, researchers can make adjustments and modifications to enhance the precision and reliability of future measurements.

4. Comparison of Experimental Methods: Researchers can use percent error as a standardized metric to compare the accuracy of different experimental methods, allowing them to evaluate performance, select the most reliable approach, and optimize methods for improved data quality and scientific understanding.

5. Quality Control and Decision-Making: Percent error serves as a tool for quality control in manufacturing processes by assessing accuracy, identifying deviations from expected values, and enabling corrective actions to maintain high-quality standards. Additionally, it aids decision-making by providing quantitative information on measurement reliability, allowing researchers and decision-makers to make informed choices based on the required level of accuracy.

Percent error formula

The formula used in our percent error calculator is derived from the following equation:

Percent error = (TV - OV) / TV × 100%,


TV represents the true value
OV represents the observed value

How to calculate percent error using Calculator Town

The Percent Error Calculator offers a convenient way to compute percent error quickly and accurately. To use it effectively, follow these simple steps:

Step 1: Navigate to the Calculator Town website and find the Percent Error Calculator.
Step 2: Enter the true value in the field provided.
Step 3: Enter the observed value in the input field.
Step 4: The percent error is then displayed automatically in the output field.
Step 5: Examine the percentage error value obtained from the calculator. A high level of accuracy is indicated by a percent error close to zero. A higher percentage error indicates a more significant deviation from the accepted value, implying a less precise measurement.
Step 6: Consider the percent error in the context of the specific measurement and its associated uncertainties. Evaluate potential sources of error.


The examples that follow use various starting points and measurement units. Our calculator can be used to verify each of them.

Example 1 Say a student’s scale recorded his weight as 158 lb., but his weight is known to be 164 lb. What is the percent error of the scale? On the calculator, enter the values as follows; Observed Value 158 True Value 164 Percent error: -3.6585365853658534%error

Example 2 Say you are purchasing wooden laths to make a treehouse. You order laths of 10 feet (304.8 cm), but upon receiving them, you get laths that are 10 ft 1 inch (307.34 cm) long. How much is that as a percent error? Enter values as follows; Observed Value 307.34 True Value 304.8 Percent error: 0.8333333333333214%error

Example 3 Assume you conducted an experiment to determine the boiling point of water and obtained an average result of 101.8°C. This is the result of your experiment or measurement because the actual boiling point of water is 100°C, the theoretical value. You want to calculate the percentage error of the average boiling point of water in your experiment, which is 101.8°C relative to 100°C. Plug your numbers into the percent error calculator: Observed Value 101.8 True Value 100 Percent error: 1.7999999999999972%error

Example 4 At the concert, it was estimated by the organizers that 90 people would show up, but in fact, 120 people came to the concert. Calculate the per cent error in the guess value of organizers. The percent error is determined as follows; Observed Value 90 True Value 120 Percent error: -25%error

Applications of Percent Error

Percent error has many important applications in experimental science and research. Some of the main uses of percent error include:


In summary, percent error is an important experimental research and analysis concept. The percent error gives a quantitative assessment of a measurement's accuracy, which aids in validating and refining experimental data. The percent error calculator at Calculator Town makes this critical task more accessible by providing a user-friendly interface and an efficient method of calculating percent error. Researchers can easily evaluate their measurements, identify areas for improvement, and contribute to the advancement of knowledge and innovation in their respective fields by effectively utilizing this online tool.

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