The SUM function

The SUM function is often the first function Excel users learn. That is why I try here to explain in detail how to use the SUM function in Excel.

Excel’s built-in function for adding numbers is called SUM and is written:
SUM(number1,number2,...])

If we break the above down step by step, you write:

1. SUM – the name of the function
2. ( – opening parenthesis
3. number1 – the first number you want to add
4. , – separator
5. number2 – the second number you want to add
6. ,... – if you want to add more numbers, you continue with more separators and numbers
7. ) – closing parenthesis

Adding numbers

You can use the SUM function to calculate the total of as many numbers as you like. By typing =SUM(10,10,10) in the formula bar (as in the example below) and pressing Enter, you calculate 10+10+10. Had you instead typed =SUM(1,3,10,-2), the result would have been 1+3+10+-2=12.

Adding values from other cells

You can also add values from other cells. In the example below I add the values from B1, B2 and B3. When I enter the function and press Enter, I get the correct answer, 30.

Adding values from cell ranges

In the example above I specified references to individual cells as number1, number2 and number3. You can also specify references to cell ranges, as in the example below. A cell range is written as start cell:end cell. Note that the start cell and the end cell are joined by a colon. In that example every cell in the range is added, just as if we had specified the cells one by one. SUM(B1:B3) is therefore the same as SUM(B1,B2,B3).

Adding a combination of numbers, values from other cells and values from cell ranges

You can add a combination of numbers, values from other cells and values from cell ranges in one and the same SUM function, as the example below illustrates.

I hope you have now learned what you needed about the Excel function SUM and feel that you have mastered the formula.