Create a Lookup Column Between Two Lists: Practical Checklist for SharePoint Owners

SharePoint site owners often need to connect data between two lists without copying information manually. A lookup column lets you display a value from one list in another list, keeping data consistent and reducing errors. This article explains how to create a lookup column between two lists and provides a practical checklist to avoid common mistakes. You will learn the prerequisites, step-by-step setup, and what to do when the lookup does not work as expected.

What Is a Lookup Column and When Should You Use One

A lookup column in SharePoint is a special column type that pulls a value from another list on the same site. For example, you can have a Projects list and a Tasks list. The Tasks list can include a lookup column that shows the Project Name from the Projects list. This ensures that every task is linked to a valid project and that the project name is always spelled the same way.

The lookup column can display any single line of text column from the source list. It can also show multiple values if you enable that option. You cannot use a lookup column to pull data from a column that is itself a lookup, from a calculated column, or from a column that supports multiple lines of text. The source list must be in the same site as the target list. Cross-site lookups are not supported in SharePoint without custom development.

Use a lookup column when you need to enforce data consistency, reduce manual entry, or create a relationship between two lists. Do not use a lookup column if the source list will change frequently in ways that break existing references, or if you need to store a snapshot of the data at a specific point in time. For snapshots, copy the value manually or use a workflow.

Prerequisites for Creating a Lookup Column

Before you create a lookup column, verify the following conditions are met:

• You have at least Edit permission level on both the source list and the target list.
• Both lists exist in the same SharePoint site. You cannot create a lookup column that references a list in a different site.
• The source list has at least one single line of text column that will serve as the lookup value. The column cannot be a calculated column, a lookup column itself, or a multiple lines of text column.
• You know the exact name of the source list and the column you want to display.

Steps to Create a Lookup Column Between Two Lists

Follow these steps to add a lookup column to a target list. The process uses the modern SharePoint experience.

1. Navigate to the target list
   Open the SharePoint site that contains both lists. Click the target list in the left navigation or go to Site contents and click the list name.
2. Open the Add Column menu
   At the top of the list, click the plus sign + Add column. If you do not see this button, click the list header area and select Add column from the dropdown.
3. Choose the Lookup column type
   From the column type menu, select Lookup. A new pane opens on the right side of the screen.
4. Enter a name for the column
   In the Name field, type a descriptive name such as ProjectName or Department.
5. Select the source list
   In the Get information from section, click the dropdown and choose the list that contains the data you want to display. Only lists in the current site appear in this list.
6. Choose the column to display
   In the In this column dropdown, select the single line of text column from the source list that you want to show in the target list. For example, if the source list is Projects and you want to show the Project Name, select that column.
7. Set additional options (optional)
   Check Allow multiple values if you want users to select more than one item from the source list. Leave this unchecked for a single-value lookup. You can also add a description and require the column to contain a value.
8. Save the column
   Click Save. The lookup column now appears in the target list. When users add or edit an item, they see a dropdown list populated with values from the source list.

Common Mistakes and Limitations When Using Lookup Columns

Lookup column shows no values in the dropdown

If the dropdown is empty, the source list might have no items, or the column you selected might be empty in all existing items. Add at least one item to the source list with a value in the referenced column. Also verify that the source list column is a single line of text and not another lookup or calculated column.

Lookup column breaks after renaming the source list or column

Renaming the source list or the column used in the lookup will cause the lookup column to stop working. SharePoint does not update the reference automatically. To fix this, delete the lookup column from the target list and recreate it with the correct source list name or column name.

Lookup column cannot be used across sites

SharePoint lookup columns work only within the same site. If you need to reference data from another site, consider using Power Apps to create a custom form with a data source from the external site, or use SharePoint search web parts to display cross-site data.

Performance degrades with large source lists

If the source list contains more than 5000 items, the lookup column may load slowly or time out. To improve performance, create an index on the lookup column in the target list. Go to the target list settings, click Indexed columns, and add the lookup column to the index. Also consider filtering the source list view to reduce the number of items shown in the dropdown.

Lookup Column vs Choice Column: Key Differences

Item	Lookup Column	Choice Column
Data source	Values come from a column in another list	Values are manually entered in column settings
Data consistency	Always reflects the current source list data	Static unless manually updated
Cross-site support	Only within the same site	Works anywhere, values are independent
Multiple selection	Supported with Allow multiple values option	Supported with Checkboxes option
Performance impact	Slower with large source lists	No performance impact from other lists

Use a lookup column when you need to keep data synchronized with a master list. Use a choice column when you have a small, static set of options that do not change often.

You can now create lookup columns between two lists in SharePoint with confidence. Start by checking the prerequisites and then follow the step-by-step setup. After creating the column, test it by adding an item to the target list and selecting a value from the dropdown. If you encounter empty dropdowns or slow loading, review the source list size and consider adding an index to the lookup column. For advanced scenarios, explore using Power Apps to create cross-site lookups with custom forms.