1.    Select the cell that will contain the result.

    2.    Do one of the following to open the Insert Function dialog box:

• Select Insert -> Function...
• Click the Sum button in the Standard toolbar and then select More Functions...:
  
• Click the Insert Function button in the left of the edit bar:
  

    3.    In the Insert Function dialog box:

• select Math & Trig in the Or select a category listbox
• select SUMIF in the Select a function list

Then press OK.

    4.    In the Function Arguments dialog box, fill following fields:

• The Range field determines the range of cells Excel will look to perform the count in. In this example the cell range is B2:B20.
• The Criteria is a conditional statement that is similar to the conditional statement in the IF statement.
• The Sum_range field tells Excel which cells to add when the criteria is met for each cell in the range. In this example the cell range is D2:D20

    5.    Press OK.

NOTE: You can enter this formula using keyboard, for this example:

=SUMIF(B2:B20,"Stephen Revay",D2:D20)

NOTE:

• You can use the wildcard characters, question mark (?) and asterisk (*), in criteria. A question mark matches any single character; an asterisk matches any sequence of characters. If you want to find an actual question mark or asterisk, type a tilde (~) before the character. For example:
  
• Microsoft Excel provides additional functions that can be used to analyse your data based on a condition or criteria:
  • To count the number of occurrences of a string of text or a number within a range of cells, use the COUNTIF function (see How to count cells by criteria for more details).
  • To have a formula return one of two values based on a condition, use the IF function.
  • To analyse data in a list based on criteria, such as profit margins or product types, use the database and list management functions (DCOUNT, DCOUNTA, DSUM etc.).