What Is a Percent Error Calculator?
A percent error calculator helps determine how far a measured (experimental) value differs from the accepted (theoretical) value in percentage terms. It is widely used in physics, chemistry, engineering, and laboratory experiments.
Percent Error Formula
Percent Error = |Experimental − Theoretical| ÷ |Theoretical| × 100
Where:
- Experimental Value = measured or observed value
- Theoretical Value = true or accepted value
- | | indicates absolute value
Step-by-Step Example
Suppose the theoretical value is 50 and your experimental value is 47.
- Step 1: Difference = 47 − 50 = -3
- Step 2: Absolute Difference = | -3 | = 3
- Step 3: Percent Error = (3 ÷ 50) × 100
- Step 4: Percent Error = 6%
This means your measured value differs from the accepted value by 6%.
Why Percent Error Matters
Percent error helps evaluate accuracy in experiments. A smaller percent error indicates higher accuracy.
When to Use This Calculator
- Science lab experiments
- Physics calculations
- Chemistry measurements
- Engineering testing
- Quality control analysis
Common Mistakes to Avoid
- Forgetting absolute value
- Using wrong denominator
- Dividing by experimental instead of theoretical value
- Using zero as theoretical value
Interpretation of Results
0% error means perfect accuracy. Low percentage (1–5%) indicates high precision. Higher percentages indicate measurement deviation.