Accounting requires accurate arithmetic to provide reliable information. Cross-footing is a method accountants use to verify that all the numbers add up. In accounting lingo, summing a column of numbers is called footing. To cross-foot is to ensure that the sum of column totals equals the grand total.

Rows and Columns

Spreadsheets lay out numbers in rows and columns, each of which can be totaled. Imagine a sheet showing monthly sales revenue for five products over the course of a year. Each of the five rows reports one product and each of the 12 columns reports one month. A sixth row totals the month's sales and a 13th column sums the annual sales per product. Cross-footing verifies that the sum of the monthly sales in row 6 equals the sum of the annual sales per product in column 13. This sum is the grand total, located in row 6, column 13.