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Mathematics & Percentages

Percentage Variance Calculator

Find the variance between two numbers as an amount and as a percentage, and see whether it is favourable for budgets, costs, sales or scores.

Also searched as: variance between two numbers · calculate variance percentage · how to calculate variance between two numbers · budget vs actual variance · percent variance

Your inputs

Results

Percentage variance

25%

Variance (actual − original)
20
Direction
Increase
Assessment
Favourable
Actual as a multiple of the original
1.25
Percentage difference (relative to the average)
22.222222%

✓Exact calculation — rounded only for display

What if?

Pick an input and drag the slider to see how the result changes.

What this calculator does

Variance compares an actual or new figure with an original, budgeted or expected one. The amount tells you how far apart the numbers are; the percentage tells you how large that gap is relative to the original. Choose whether higher or lower is good, and the tool also tells you whether the variance is favourable.

Formula and method

Variance = actual − original Percentage variance = (actual − original) ÷ |original| × 100 Multiple = actual ÷ original Percentage difference = |actual − original| ÷ ((|actual| + |original|) ÷ 2) × 100

Worked example

Calculated by this tool with its default inputs:

Inputs

  • Original, budgeted or expected value: 80
  • New or actual value: 100
  • Which direction is good?: Higher is better (revenue, profit, score)

Results

  • Percentage variance: 25%
  • Variance (actual − original): 20
  • Direction: Increase
  • Assessment: Favourable
  • Actual as a multiple of the original: 1.25
  • Percentage difference (relative to the average): 22.222222%

How to read the results

A positive percentage means the actual figure is above the original. Whether that is good depends on what you measure: more revenue is favourable, more cost is not. The percentage difference uses the average of both numbers as the base and does not depend on which one is called original.

Assumptions and limitations

  • The percentage is measured against the original value, so swapping the two numbers gives a different percentage.
  • Not to be confused with statistical variance (the average squared deviation of a data set); use the variance calculator for that.

Questions

How do I calculate the variance between two numbers?

Subtract the original from the new number to get the variance, then divide by the original and multiply by 100 for the percentage variance.

What is the difference between percentage variance and percentage difference?

Percentage variance measures the change from a chosen starting value. Percentage difference compares two values symmetrically against their average, so it does not matter which is first.

Why can the tool not use an original value of zero?

A percentage of zero is undefined, so there is nothing to divide by. Use the absolute variance instead.

Methodology and verification

Result type
Exact mathematical calculation (rounded only for display)
Formula version
1.0
Automated verification
5 reference and validation test cases, checked against independently computed values. The site cannot be built if any of them fail.
Editorial review
Awaiting human editorial review. The explanation was drafted with AI assistance; the formula and examples are verified by the automated tests above.

Privacy

Everything you enter is calculated in this browser and is not sent to Numerith or anyone else. Inputs are added to a share link only if you choose to include them. Privacy policy