Can percent error be negative?

Standard scientific convention uses the absolute value, ensuring percent error is always positive. When directional bias is analyzed, signed relative error without the absolute value is used.

CalcivoTools

Percent Error Calculator : Experimental vs Accepted Theoretical Value

The Calcivo Percent Error Calculator determines experimental precision in scientific labs and engineering measurements. It computes the absolute error, relative decimal error, and percent error by comparing your measured experimental value against the accepted standard value.

Interactive Calculator

100% Client-Side Engine

Percent Error (|Exp - Acc| / |Acc| × 100)

0.1361%

Absolute Error

0.0134

Relative Error (Decimal)

0.001361

Step-by-Step Derivation

1. Absolute Error = |Experimental - Accepted| = |9.82 - 9.80665| = 0.0134

2. Relative Error = Absolute Error / |Accepted| = 0.0134 / |9.80665| = 0.001361

3. Percent Error = Relative Error × 100 = 0.001361 × 100 = 0.1361%

Step-by-Step Examples

Gravitational Acceleration Experiment

Measured g = 9.82 m/s² vs accepted g = 9.80665 m/s².

Inputs: Experimental: 9.82, Accepted: 9.80665

Result: 0.1361% Error (Absolute: 0.01335)

(|9.82 - 9.80665| / 9.80665) × 100 = (0.01335 / 9.80665) × 100 = 0.1361%.

How to Use This Tool

Enter your observed / experimental measured value.
Enter the true / accepted theoretical value.
Click Calculate to view the percent error, absolute error, and relative deviation.

Frequently Asked Questions

In general high school and university physics/chemistry labs, a percent error under 5% is considered very accurate, and under 10% is typically acceptable depending on instrument tolerances.

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