How to Calculate Variance Percentage Between Budget and Actual
Percentage variance shows how far actual performance drifted from plan, scaled to the size of the plan. It is the core number in every management report: (actual − budget) ÷ budget × 100, labelled favourable or adverse depending on whether the line is income or cost.
Favourable and adverse
- Revenue above budget → favourable. Revenue below budget → adverse.
- Cost above budget → adverse. Cost below budget → favourable.
- Always show the sign and the label; a bare '15% variance' is ambiguous.
Volume versus rate
A single percentage hides why the gap appeared. Splitting it into volume variance (you sold more or fewer units than planned) and rate or price variance (each unit cost or earned a different amount) turns a number into an action. A 15% adverse materials variance driven entirely by supplier price increases calls for a different response than one driven by scrap.
In Excel and Google Sheets
- Variance amount: =C2-B2 (actual minus budget).
- Variance percent: =(C2-B2)/ABS(B2), formatted as a percentage.
- Guard against division by zero: =IFERROR((C2-B2)/ABS(B2),"n/a").
- Conditional formatting on the percentage column flags breaches automatically.
Setting materiality thresholds
Investigating every wobble wastes time. Most teams set a dual threshold — for example anything beyond ±5% and above a fixed currency amount — so a 40% variance on a tiny line does not outrank a 3% variance on the largest cost in the business.
Key takeaways — Percentage Variance Calculator
- Variance % = (actual − budget) ÷ |budget| × 100.
- Label every variance favourable or adverse; the sign alone is not enough.
- Split large variances into volume and rate before explaining them.