What is the difference between a formula and a function?

A formula is any expression that calculates a value, e.g., =A1+A2. A function is a predefined formula in software like Excel, e.g., =SUM(A1:A10). So, every function is part of a formula, but not every formula is a function.

Think of formulas as “custom math you write” and functions as “ready-made tools” the software gives you.