wikiHow Percentage Error Calculator Percentage error is a way to quantify the difference between an estimated or measured value and the true or accepted value, expressed as a percentage. The formula to calculate the percentage error is: Percentage Error = (|Measured Value - True Value| / True Value) × 100% Here are the steps to calculate the percentage error: 1. Determine the measured value: This is the value obtained through measurement or estimation. 2. Determine the true value: This is the accepted or known value, typically obtained from a reference source or through precise measurement. 3. Calculate the absolute difference: Subtract the true value from the measured value and take the absolute value of the difference. 4. Divide the absolute difference by the true value. 5. Multiply the result by 100% to express the error as a percentage. The formula ensures that the error is positive regardless of whether the measured value is greater or smaller than the true value. It's important to note that percentage error is a relative measure and provides an indication of the magnitude of the difference between the measured and true values, expressed as a percentage of the true value. Positive percentage error indicates an overestimate, while negative percentage error indicates an underestimate. Now that you know the steps, you can use the formula to calculate the percentage error for any given situation. Example: A student measures the length of a table and obtains a value of 150 cm. The true length of the table, as measured by an accurate ruler, is 160 cm. Calculate the percentage error in the student's measurement. Step 1: Determine the measured value: The measured value by the student is 150 cm. Step 2: Determine the true value: The true value of the table's length is 160 cm. Step 3: Calculate the absolute difference: Absolute difference = |Measured Value - True Value| = |150 cm - 160 cm| = 10 cm Step 4: Divide the absolute difference by the true value: 10 cm / 160 cm = 0.0625 Step 5: Multiply the result by 100% to express the error as a percentage: 0.0625 × 100% = 6.25% The percentage error in the student's measurement is 6.25%. This means that the student's measurement of 150 cm deviates from the true value of 160 cm by approximately 6.25%. Page