The DATEVALUE function takes a piece of text in the form of a date and converts it into a number representing the Microsoft Excel date-time code. An important function to know for use in dashboard construction and use with lookup problems involving date/times.
The DATEVALUE function is a computer program that you run from a worksheet cell formula. It converts a date that is stored as text to a serial date number that Excel recognizes as a date. You run the DATEVALUE function by typing its name in a formula then followed by the information it is suppose to use. The DATEVALUE worksheet function is used with functions like the VLOOKUP, MATCH and similar functions because when they lookup dates they are looking for the serial number not the date format. In other words, you cannot simply type 1/1/2015 as their argument or "1/1/2015" either unless you are looking for text. The DATEVALUE worksheet function is also used along with string concatenation to take pieces of text from an dashboard interface or cell data and flip those values into a date-time serial number that can be used in Microsoft Excel.
Whenever you type a formula in a worksheet cell, this is called syntax or grammar. The general DATEVALUE function syntax has a format like this when you type it in a worksheet cell:
= DATEVALUE( date_text )
Where date_text is called the function argument list. Remember, you are running a computer program at this point so the program needs information to operate and that is why there is an argument list. When you see an argument list and you see square brackets [ ] around the argument name, this means the argument is optional and you do not have to include it when typing unless you need it. So for the syntax above, you need to include 1 argument for the DATEVALUE function when typing it in a worksheet cell formula in order for it to calculate correctly. What argument value can be used is discussed below. Remember functions expect certain things in their argument lists, if you do not put the correct information in the list they will generate an error when run.
Since the DATEVALUE function is a computer program, it runs when you press Enter to enter the formula that contains it. If any of its arguments are wrong, the function will return an error.
When typing the DATEVALUE function in a worksheet cell formula, you need to replace the date_text argument with something that generates date text needed. Some typical arguments you can use are:
|Argument Type||Cell Formula||Example Explanation|
|Cell Reference||= DATEVALUE( A1 )||Returns a serial date number based upon what text is in cell A1. For example if "1/1/2015" was in cell A1 then 42005 would be returned|
|Range Reference||= DATEVALUE( A1:A10 )||Returns an array of serial date numbers based upon the date text in cells A1 to A10|
|String Concatenation||= DATEVALUE( A1 & "/" & A2 & "/" & A3 )||Returns a serial date number based upon what text is in cell's A1, A2 and A3. The string concatenation puts the date together. Very common argument type for dashboard problems and from data stored in multiple columns|
The worksheet seen below contains some typical worksheet formulas that run the DATEVALUE and DATE worksheet function. Pay close attention to the argument list and the syntax used to write the formula.
|4||Formula below splices date together from table above so VLOOKUP can use it to lookup a serial date number in another table|
|5||= VLOOKUP ( DATEVALUE( A2 & "/" & B2 & "/" & C2), $G$1:$K$100, 3, FALSE )|
|6||You can also use the DATE function for the same effect when dealing with number in seperate columns|
|= VLOOKUP ( DATE( C2, A2, B2 ), $G$1:$K$100, 3, FALSE )|