1. What is Percent Difference?

Percent difference measures the relative difference between two values as a percentage of their average. It's commonly used to compare experimental values, measurements, or any two quantities where neither can be considered a "reference" or "true" value.

2. How Does the Calculator Work?

The calculator uses the percent difference formula:

Where:

• \( \text{New Value} \) — The newer or second measurement
• \( \text{Old Value} \) — The older or first measurement
• \( | \cdot | \) — Absolute value (always positive)

Explanation: The formula calculates the absolute difference between two values relative to their average, expressed as a percentage.

3. When to Use Percent Difference

Details: Percent difference is ideal when comparing two experimental values where neither is considered the "correct" value. It's commonly used in physics, chemistry, and engineering experiments.

4. Using the Calculator

Tips: Enter both values (order doesn't matter as the calculation uses absolute difference). The result shows what percentage the difference is relative to the average of the two values.

5. Frequently Asked Questions (FAQ)

Q1: What's the difference between percent difference and percent change?
A: Percent change compares a new value to an old reference value, while percent difference compares two values symmetrically without designating either as reference.

Q2: Can percent difference be negative?
A: No, because the formula uses absolute value. The result is always 0% or positive.

Q3: What does a 0% difference mean?
A: It means the two values are identical (no difference between them).

Q4: What's considered a "good" percent difference?
A: This depends on the context. In some experiments, <5% might be excellent, while in others, <20% might be acceptable.

Q5: How is this different from percentage error?
A: Percentage error compares a measured value to a known or accepted value, while percent difference compares two experimental values.