A PivotTable reorganizes and summarizes large datasets without writing a single formula -- dragging a 'Region' field to rows and a 'Sales' field to values instantly produces a total sales-by-region table from thousands of raw rows. Both Excel and Google Sheets support PivotTables (Sheets calls the feature 'Pivot table' under the Insert menu), and both can summarize data by sum, average, or count, and group it by multiple fields at once, such as region and month. Filters let you narrow a PivotTable to a specific time period or category without altering the underlying raw data, which makes PivotTables ideal for exploring 'what if I only look at...' questions quickly. For any dataset with repeated categories, such as sales records, survey responses, or inventory logs, a PivotTable is almost always faster than building the same summary with manual formulas.