Tip: Try using the new XLOOKUP function, an improved version of VLOOKUP that works in any direction and returns exact matches by default, making it easier and more convenient to use than its predecessor.
Use VLOOKUP when you need to find things in a table or a range by row. For example, look up a price of an automotive part by the part number, or find an employee name based on their employee ID.
In its simplest form, the VLOOKUP function says:
=VLOOKUP(What you want to look up, where you want to look for it, the column number in the range containing the value to return, return an Approximate or Exact match – indicated as 1/TRUE, or 0/FALSE).
Tip: The secret to VLOOKUP is to organize your data so that the value you look up (Fruit) is to the left of the return value (Amount) you want to find.
Technical details
Use the VLOOKUP function to look up a value in a table.
Syntax
VLOOKUP (lookup_value, table_array, col_index_num, [range_lookup])
For example:

=VLOOKUP(A2,A10:C20,2,TRUE)

=VLOOKUP("Fontana",B2:E7,2,FALSE)

=VLOOKUP(A2,’Client Details’!A:F,3,FALSE)
Argument name 
Description 

lookup_value (required) 
The value you want to look up. The value you want to look up must be in the first column of the range of cells you specify in the table_array argument. For example, if tablearray spans cells B2:D7, then your lookup_value must be in column B. Lookup_value can be a value or a reference to a cell. 
table_array (required) 
The range of cells in which the VLOOKUP will search for the lookup_value and the return value. You can use a named range or a table, and you can use names in the argument instead of cell references. The first column in the cell range must contain the lookup_value. The cell range also needs to include the return value you want to find. Learn how to select ranges in a worksheet. 
col_index_num (required) 
The column number (starting with 1 for the leftmost column of table_array) that contains the return value. 
range_lookup (optional) 
A logical value that specifies whether you want VLOOKUP to find an approximate or an exact match:

How to get started
There are four pieces of information that you will need in order to build the VLOOKUP syntax:

The value you want to look up, also called the lookup value.

The range where the lookup value is located. Remember that the lookup value should always be in the first column in the range for VLOOKUP to work correctly. For example, if your lookup value is in cell C2 then your range should start with C.

The column number in the range that contains the return value. For example, if you specify B2:D11 as the range, you should count B as the first column, C as the second, and so on.

Optionally, you can specify TRUE if you want an approximate match or FALSE if you want an exact match of the return value. If you don't specify anything, the default value will always be TRUE or approximate match.
Now put all of the above together as follows:
=VLOOKUP(lookup value, range containing the lookup value, the column number in the range containing the return value, Approximate match (TRUE) or Exact match (FALSE)).
Examples
Here are a few examples of VLOOKUP:
Example 1
Example 2
Example 3
Example 4
Example 5
Combine data from several tables onto one worksheet by using VLOOKUP
You can use VLOOKUP to combine multiple tables into one, as long as one of the tables has fields in common with all the others. This can be especially useful if you need to share a workbook with people who have older versions of Excel that don't support data features with multiple tables as data sources  by combining the sources into one table and changing the data feature's data source to the new table, the data feature can be used in older Excel versions (provided the data feature itself is supported by the older version).
Here, columns AF and H have values or formulas that only use values on the worksheet, and the rest of the columns use VLOOKUP and the values of column A (Client Code) and column B (Attorney) to get data from other tables. 

Copy the table that has the common fields onto a new worksheet, and give it a name.

Click Data > Data Tools > Relationships to open the Manage Relationships dialog box.

For each listed relationship, note the following:

The field that links the tables (listed in parentheses in the dialog box). This is the lookup_value for your VLOOKUP formula.

The Related Lookup Table name. This is the table_array in your VLOOKUP formula.

The field (column) in the Related Lookup Table that has the data you want in your new column. This information is not shown in the Manage Relationships dialog  you'll have to look at the Related Lookup Table to see which field you want to retrieve. You want to note the column number (A=1)  this is the col_index_num in your formula.


To add a field to the new table, enter your VLOOKUP formula in the first empty column using the information you gathered in step 3.
In our example, column G uses Attorney (the lookup_value) to get the Bill Rate data from the fourth column (col_index_num = 4) from the Attorneys worksheet table, tblAttorneys (the table_array), with the formula =VLOOKUP([@Attorney],tbl_Attorneys,4,FALSE).
The formula could also use a cell reference and a range reference. In our example, it would be =VLOOKUP(A2,'Attorneys'!A:D,4,FALSE).

Continue adding fields until you have all the fields that you need. If you are trying to prepare a workbook containing data features that use multiple tables, change the data source of the data feature to the new table.
Common Problems
Problem 
What went wrong 

Wrong value returned 
If range_lookup is TRUE or left out, the first column needs to be sorted alphabetically or numerically. If the first column isn't sorted, the return value might be something you don't expect. Either sort the first column, or use FALSE for an exact match. 
#N/A in cell 
For more information on resolving #N/A errors in VLOOKUP, see How to correct a #N/A error in the VLOOKUP function. 
#REF! in cell 
If col_index_num is greater than the number of columns in tablearray, you'll get the #REF! error value. For more information on resolving #REF! errors in VLOOKUP, see How to correct a #REF! error. 
#VALUE! in cell 
If the table_array is less than 1, you'll get the #VALUE! error value. For more information on resolving #VALUE! errors in VLOOKUP, see How to correct a #VALUE! error in the VLOOKUP function. 
#NAME? in cell 
The #NAME? error value usually means that the formula is missing quotes. To look up a person's name, make sure you use quotes around the name in the formula. For example, enter the name as "Fontana" in =VLOOKUP("Fontana",B2:E7,2,FALSE). For more information, see How to correct a #NAME! error. 
#SPILL! in cell 
This particular #SPILL! error usually means that your formula is relying on implicit intersection for the lookup value, and using an entire column as a reference. For example, =VLOOKUP(A:A,A:C,2,FALSE). You can resolve the issue by anchoring the lookup reference with the @ operator like this: =VLOOKUP(@A:A,A:C,2,FALSE). Alternatively, you can use the traditional VLOOKUP method and refer to a single cell instead of an entire column: =VLOOKUP(A2,A:C,2,FALSE). 
Best practices
Do this 
Why 

Use absolute references for range_lookup 
Using absolute references allows you to filldown a formula so that it always looks at the same exact lookup range. Learn how to use absolute cell references. 
Don't store number or date values as text. 
When searching number or date values, be sure the data in the first column of table_array isn't stored as text values. Otherwise, VLOOKUP might return an incorrect or unexpected value. 
Sort the first column 
Sort the first column of the table_array before using VLOOKUP when range_lookup is TRUE. 
Use wildcard characters 
If range_lookup is FALSE and lookup_value is text, you can use the wildcard characters—the question mark (?) and asterisk (*)—in lookup_value. 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 (~) in front of the character. For example, =VLOOKUP("Fontan?",B2:E7,2,FALSE) will search for all instances of Fontana with a last letter that could vary. 
Make sure your data doesn't contain erroneous characters. 
When searching text values in the first column, make sure the data in the first column doesn't have leading spaces, trailing spaces, inconsistent use of straight ( ' or " ) and curly ( ‘ or “) quotation marks, or nonprinting characters. In these cases, VLOOKUP might return an unexpected value. To get accurate results, try using the CLEAN function or the TRIM function to remove trailing spaces after table values in a cell. 
Need more help?
You can always ask an expert in the Excel Tech Community or get support in the Answers community.
See Also
Quick Reference Card: VLOOKUP refresher
Quick Reference Card: VLOOKUP troubleshooting tips
How to correct a #VALUE! error in the VLOOKUP function
How to correct a #N/A error in the VLOOKUP function
Overview of formulas in Excel
How to avoid broken formulas
Detect errors in formulas
Excel functions (alphabetical)
Excel functions (by category)
VLOOKUP (free preview)