Percent Error Calculator
Calculate the percent error between an experimental value and a theoretical value.
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Table of Contents
Percent Error Formula
Percent error is a measure of the accuracy of a measurement compared to a theoretical value.
Where:
- Experimental is the measured value
- Theoretical is the expected value
- | | represents absolute value
How to Calculate Percent Error
To calculate percent error, follow these steps:
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1Subtract the theoretical value from the experimental value
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2Take the absolute value of the difference
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3Divide by the theoretical value
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4Multiply by 100 to get the percentage
Interpreting Results
Understanding percent error results:
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1Small Percent Error:
Indicates high accuracy in your measurements.
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2Large Percent Error:
Suggests potential issues with measurement or experimental setup.
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3Zero Percent Error:
Perfect match between experimental and theoretical values (rare in practice).
Practical Examples
Example 1 Density Measurement
Measuring the density of water (theoretical = 1.00 g/mL).
Experimental = 0.98 g/mL
Theoretical = 1.00 g/mL
Percent Error = |(0.98 - 1.00) / 1.00| × 100% = 2%
Example 2 Temperature Reading
Measuring room temperature (theoretical = 25°C).
Experimental = 26.5°C
Theoretical = 25.0°C
Percent Error = |(26.5 - 25.0) / 25.0| × 100% = 6%
Example 3 Mass Measurement
Weighing a standard 100g mass.
Experimental = 99.8g
Theoretical = 100.0g
Percent Error = |(99.8 - 100.0) / 100.0| × 100% = 0.2%