# LOOKUP function

This article describes the formula syntax and usage of the **LOOKUP** function (function: A prewritten formula that takes a value or values, performs an operation, and returns a value or values. Use functions to simplify and shorten formulas on a worksheet, especially those that perform lengthy or complex calculations.) in Microsoft Excel.

## 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.

## Vector form

A vector is a range of only one row or one column. The vector form of **LOOKUP** looks in a one-row or one-column range (known as a vector) for a value and returns a value from the same position in a second one-row or one-column range. Use this form of the **LOOKUP** function when you want to specify the range that contains the values that you want to match. The other form of **LOOKUP** automatically looks in the first column or row.

### Syntax

LOOKUP(lookup_value, lookup_vector, [result_vector])

The **LOOKUP** function vector form syntax has the following arguments (argument: A value that provides information to an action, an event, a method, a property, a function, or a procedure.):

**lookup_value**Required. A value that**LOOKUP**searches for in the first vector.can be a number, text, a logical value, or a name or reference that refers to a value.*Lookup_value***lookup_vector**Required. A range that contains only one row or one column. The values incan be text, numbers, or logical values.*lookup_vector*

** Important ** The values in ** lookup_vector** must be placed in ascending order: ..., -2, -1, 0, 1, 2, ..., A-Z, FALSE, TRUE; otherwise,

**LOOKUP**might not return the correct value. Uppercase and lowercase text are equivalent.

**result_vector**Optional. A range that contains only one row or column. Theargument must be the same size as*result_vector*.*lookup_vector*

### Remarks

- If the
**LOOKUP**function can't find the, the function matches the largest value in*lookup_value*that is less than or equal to*lookup_vector*.*lookup_value* - If
is smaller than the smallest value in*lookup_value*,*lookup_vector***LOOKUP**returns the #N/A error value.

## Examples

### Example 1

Use the embedded workbook shown here to work with examples of this function. You can inspect and change existing formulas, enter your own formulas, and read further information about how the function works.

This example uses the LOOKUP function in vector form, looking in a range of just a one-row or a one-column range

To work in-depth with this workbook, you can download it to your computer and open it in Excel. For more information, see the article Download an embedded workbook from OneDrive and open it on your computer.

### Example 2

This array form example assigns letter-grade values for test scores.