Percent Error Calculator

Theoretical / Accepted Value Experimental / Measured Value

Percent Error Calculator Online – Calculate Accuracy Easily

Intro

A Percent Error Calculator online is a simple yet powerful tool that helps you measure the accuracy of an experimental value compared to a known or accepted value. It is widely used in science, mathematics, engineering, and laboratory work to determine how close your measured results are to the expected values.

Percent error expresses the difference between an experimental result and the true value as a percentage. Instead of manually solving equations, this tool provides quick and accurate results, saving time and reducing human error.

Whether you are a student working on lab experiments, a teacher grading assignments, or a researcher testing accuracy, the Percent Error Calculator makes the process fast and stress-free.

Formula / Working

The formula for calculating percent error is: Percent Error=(∣Experimental Value−Theoretical Value∣∣Theoretical Value∣)×100\text{Percent Error} = \left( \frac{|\text{Experimental Value} – \text{Theoretical Value}|}{|\text{Theoretical Value}|} \right) \times 100Percent Error=(∣Theoretical Value∣∣Experimental Value−Theoretical Value∣)×100

Where:

Experimental Value (Observed Value): The value you measured in your experiment.
Theoretical Value (True/Accepted Value): The actual or correct value.
| | (Absolute Value): Ensures the error is always positive.

This formula tells us the size of the error relative to the true value, expressed as a percentage.

Step-by-Step Usage

Here’s how to use the Percent Error Calculator online:

Enter the experimental (observed) value.
Enter the theoretical (true/accepted) value.
Click Calculate.
The calculator will display the percent error (%) instantly.

Examples

Example 1: Chemistry Experiment

Experimental Value = 9.8 g
Theoretical Value = 10 g

Percent Error=(∣9.8−10∣10)×100\text{Percent Error} = \left( \frac{|9.8 – 10|}{10} \right) \times 100Percent Error=(10∣9.8−10∣)×100 =(0.210)×100=2%= \left( \frac{0.2}{10} \right) \times 100 = 2\%=(100.2)×100=2%

✅ Percent error = 2%

Example 2: Physics Measurement

Experimental Value = 50.5 m/s
Theoretical Value = 52 m/s

Percent Error=(∣50.5−52∣52)×100\text{Percent Error} = \left( \frac{|50.5 – 52|}{52} \right) \times 100Percent Error=(52∣50.5−52∣)×100 =(1.552)×100≈2.88%= \left( \frac{1.5}{52} \right) \times 100 \approx 2.88\%=(521.5)×100≈2.88%

✅ Percent error = 2.88%

Example 3: Business Forecasting

Experimental Value = $480,000 (forecast)
Theoretical Value = $500,000 (actual sales)

Percent Error=(∣480,000−500,000∣500,000)×100\text{Percent Error} = \left( \frac{|480,000 – 500,000|}{500,000} \right) \times 100Percent Error=(500,000∣480,000−500,000∣)×100 =(20,000500,000)×100=4%= \left( \frac{20,000}{500,000} \right) \times 100 = 4\%=(500,00020,000)×100=4%

✅ Percent error = 4%

FAQs

1. What is a Percent Error Calculator?
It’s an online tool that calculates how accurate an experimental value is compared to a true value, expressed as a percentage.

2. Why is percent error important?
It helps determine the accuracy of experiments, forecasts, and measurements.

3. Can percent error be negative?
No, since absolute values are used, percent error is always positive.

4. Is a low percent error always good?
Yes, a lower percent error means higher accuracy. However, acceptable error depends on the field of study.

5. Can I use the Percent Error Calculator on my phone?
Yes, the tool is mobile-friendly and works on any device with internet access.