Percentage Change in Excel
Measure relative increase or decrease between old and new values.
What this solves
Calculate supplier price change %. This pattern is useful when the business question is clear but a generic tutorial is too abstract.
The rule
(new-old)/old, with explicit handling when old is zero.
=IF(B2=0,"",(C2-B2)/B2)Google Sheets: The core pattern is also usable in Google Sheets; exact function support and locale separators can differ.
Real-work checklist
- Define the business key and expected grain before writing the formula, query or markup.
- Test the pattern on a small known sample where you can verify the answer manually.
- Check missing values, duplicates and data types before trusting a large result.
- Scale to the real file or database only after the logic is proven.
Common mistake
A percentage change from zero is undefined; do not force a misleading percentage.