ReferenceExcel FormulasSupported FormulasSUMOn this pageSUM The SUM function adds all the numbers specified as arguments. Syntax =SUM(number1, [number2], ...) Parameters number1: The first number to add number2, ...: Optional. Additional numbers to add Examples =SUM(1, 2, 3) // Returns 6=SUM(10, -5, 15) // Returns 20=SUM(100) // Returns 100