Percent Error Calculator — Calculate Percentage Error

Percent Error Calculator

Calculate percent error, absolute error, and relative error between experimental and theoretical values. Perfect for lab reports, quality control, and data analysis.

Step 1: Enter Values

Percent Error Formula

Percent Error = |(Experimental – Theoretical) / Theoretical| × 100%

Step 2: Options & Examples

Interpretation

• Percent error near 0% indicates high accuracy.
• <5% often acceptable in many sciences.
• >10% may suggest systematic error.

Percent Error Results

Summary
Error Thresholds
Formula

Percent Error

5.00%
| (105 – 100) / 100 | × 100%
Absolute Error
5.00
Relative Error
0.0500
Experimental – Theoretical
+5.00
Accuracy (1 – rel. error)
95.00%

Common Error Thresholds

Threshold Description Your Error

Percent Error Formula

Percent Error = |(Experimental – Theoretical) / Theoretical| × 100%

Where:
• Theoretical = accepted or true value
• Experimental = measured or observed value
• |…| = absolute value (always positive)

Related:
• Absolute Error = |Experimental – Theoretical|
• Relative Error = |Experimental – Theoretical| / |Theoretical|

Example Calculation

Example: Lab Measurement

Theoretical value (accepted): 100
Experimental value (measured): 105

Calculation:
Absolute error = |105 – 100| = 5
Relative error = 5 / 100 = 0.05
Percent error = 0.05 × 100% = 5.00%

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