# The Excel function: LOOKUP

## Description

The **LOOKUP** function returns a value either from a one-row or one-column range (range: Two or more cells on a sheet. The cells in a range can be adjacent or nonadjacent.) or from an array (array: Used to build single formulas that produce multiple results or that operate on a group of arguments that are arranged in rows and columns. An array range shares a common formula; an array constant is a group of constants used as an argument.). The **LOOKUP** function has two syntax forms: the vector form and the array form.

If you want to |
Then see |
Usage |
---|---|---|

Look in a one-row or one-column range (known as a vector) for a value and return a value from the same position in a second one-row or one-column range | Vector form | Use the vector form when you have a large list of values to look up or when the values may change over time. |

Look in the first row or column of an array for the specified value and return a value from the same position in the last row or column of the array | Array form | Use the array form when you have a small list of values and the values remain constant over time. |

** Notes **

- You can also use the
**LOOKUP**function as an alternative to the**IF**function for elaborate tests or tests that exceed the limit for nesting of functions. See the examples in the array form. - For the
**LOOKUP**function to work correctly, the data being looked up must be sorted in ascending order. If this is not possible, consider using the VLOOKUP, HLOOKUP, or MATCH functions.