An Excel function is a built-in shortcut to do calculations in Excel, and it can be incorporated into any formula in any cell. A function runs a predetermined set of calculations based on input you provide it with.
For example, say you wish to calculate the value of a number raised to a certain power. For this example, we will calculate 4 raised to the power of 5.
One way to calculate this would be to type a formula that multiplies 4 with itself, 5 times. In this instance, the formula would read (notice the formula in the top right hand corner and the result in the highlighted cell):
This is not a very sustainable way of doing things. If you want to change the exponent to another value, you will have to recount the number of 4s in the formula and adjust it. The probability that you will be making an error is great. So a better way is to use the built-in Excel function called POWER. When using this function to do the calculation above, the formula would simply read:
This tells Excel to raise 4 to the power of 5. The inputs to the function (4 and 5 in this case) are enclosed in round brackets and separated by commas. In this case, the first input (4) is the base, and the second input (5) is the exponent. So to the value of 4 raised to the power of 7, simply change the formula to:
What is a function really?
In simple terms, a function is like a machine that processes input provided by you, the user, and generates output. Think of an automatic espresso machine. It takes in several inputs (coffee beans, sugar, milk, water), processes them in a very specific way, and produces an output in the form of a steaming cup of coffee!
Similarly, all Excel functions have one or more inputs and one or more outputs. To learn how to use a function, you need to read its documentation to determine the syntax (this means, the correct way to type values in the functions). You can find the documentation either within Excel itself or on this website.
Next, learn how you can easily insert a function into Excel.