Percent Error Calculator
Calculate percent error using the actual value and measured value.
The difference between 47 and 50 is 3. Divide 3 by 50 and multiply by 100 to get 6%.
Use this percent error calculator to calculate the percentage difference between an actual value and a measured value. Enter both numbers and get the percent error instantly.
The tool uses the standard percent error formula and shows how the result is calculated step by step.
How to Use the Percent Error Calculator?
Enter the actual value
This is the correct or accepted value.
Enter the measured value
This is the experimental or observed value.
Click calculate
The calculator applies the percent error formula automatically.
View the result
You will see the percent error as a percentage.
Percent Error Formula
Percent error is calculated using this formula:
| Measured Value − Actual Value | ÷ Actual Value × 100
The difference between the measured and actual values is divided by the actual value, then multiplied by 100.
What Is Percent Error?
Percent error measures how far a measured value is from the actual value.
It shows the size of the error as a percentage of the correct value.
A smaller percent error means the measurement is more accurate.
Example of Percent Error
Actual value: 50
Measured value: 47
Step 1: Find the difference
|47 − 50| = 3
Step 2: Divide by the actual value
3 ÷ 50 = 0.06
Step 3: Multiply by 100
0.06 × 100 = 6%
Percent error = 6%
How to Calculate Percent Error?
Step 1: Subtract the actual value from the measured value
Use absolute value so the result is positive.
Step 2: Divide by the actual value
This shows the size of the error relative to the correct value.
Step 3: Multiply by 100
Convert the result into a percentage.
Why Percent Error Matters?
Percent error helps measure the accuracy of data and experiments.
It is commonly used in:
Science
Physics
Chemistry
Engineering
Lab work
Measurements
Data analysis
A low percent error means the measured value is close to the accepted value.
Positive vs Negative Error
Some methods keep the sign of the error.
Positive error means the measured value is higher than the actual value.
Negative error means the measured value is lower than the actual value.
Most percent error calculations use the absolute value so the result is always positive.
Percent Error vs Absolute Error
Percent error shows the error as a percentage.
Absolute error shows the raw difference between two values.
Example:
Actual value = 100
Measured value = 96
Absolute error = 4
Percent error = 4%
Common Mistakes
Using the measured value in the denominator
The denominator should be the actual value.
Forgetting the absolute value
Percent error is usually written as a positive percentage.
Not multiplying by 100
The final answer must be converted into a percentage.
Mixing actual and measured values
Always identify the accepted value correctly.
When to Use Percent Error?
Use percent error when comparing a measured result with a known correct value.
It is useful for:
Experiments
Lab reports
Research
Quality control
Scientific calculations
Measurement analysis
FAQs
Final Section
Use this percent error calculator to quickly compare measured and actual values. Enter both numbers and get accurate percent error results instantly.