How to Create a Lookup Column in SharePoint
Lookup columns connect lists together — pick a value from another list rather than typing it. Maintain data once, use it everywhere.
What it is
A Lookup column lets users pick a value from another SharePoint list (within the same site). For example, you might have a master ‘Clients’ list with 200 client records, and a ‘Projects’ library where each project has a ‘Client’ column that’s a Lookup pointing at that Clients list. Users pick the client from a dropdown; SharePoint stores the connection. Update a client’s name in the master list, and every project that references it shows the updated name automatically.
Lookups are the right tool when you have shared reference data within a site — Clients, Projects, Departments, Categories — and you want one canonical source of truth. Without lookups, that data ends up duplicated across libraries with all the inconsistencies that come with manual entry.
The big constraint is that Lookups only work within the same site. If your reference data needs to be used across multiple sites, you need Managed Metadata instead (see M-13). For most use cases inside a single site, Lookups are simpler to set up and easier to maintain than Managed Metadata.
When to use this
- When you have a master list of reference data (Clients, Projects, Codes, Categories) used in multiple libraries on the same site.
- When you want users to pick from a list rather than type freely.
- When you need centralised maintenance — update once, reflect everywhere.
- Not when the reference data is shared across multiple sites — use Managed Metadata for that.
How to do it
- Create the master list first (e.g. a ‘Clients’ list with name, contact, etc.).
- Open the library where you want the Lookup column.
- Click + Add column → Lookup.
- Choose the source list and the column to display.
- Optionally include extra columns for richer data (e.g. show client name and contact email).
- Decide if multiple values are allowed.
- Save and start tagging items.
Best practices
- Use one master list per concept. One ‘Clients’ list, referenced by every library that needs clients.
- Enable Cascading Deletes carefully. Protects integrity but can have surprising side effects.
- Show extra columns for context. ‘Acme Corp (Sarah Smith)’ beats just ‘Acme Corp’ when there are similar names.
- Plan for cross-site needs. If reference data will eventually be needed in other sites, start with Managed Metadata instead.
Common mistakes
- Recreating the same master list in multiple sites. Defeats the purpose. Use Managed Metadata for cross-site lookups.
- Leaving the master list ungoverned. If anyone can edit it, the data quality drops fast.
- Using Lookup for stable global reference data. Departments, locations, document types belong in Managed Metadata.
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What is a Lookup column in SharePoint?
A Lookup column points at a column in another SharePoint list within the same site. Instead of typing values (or maintaining a Choice list per library), users pick from a list that’s managed centrally. Change a value in the master list and every Lookup reference picks up the change — no duplication, no inconsistency, no manual updates across libraries.
Can a SharePoint Lookup column work across different sites?
No — Lookups only work within the same SharePoint site. This is one of the biggest constraints of Lookup columns and a common reason teams hit a wall. If you need the same reference data across multiple sites, use Managed Metadata instead (it works tenant-wide), or duplicate the master list in each site (and accept the maintenance overhead).
How do I show extra columns from a Lookup source list?
When creating the Lookup column, scroll down to Add a column to show each of these additional fields and tick the extra fields you want. They’ll appear as read-only columns alongside the main Lookup. Useful pattern: Lookup to Project Name, then auto-pull Client, Project Lead, and Start Date so they appear in every library that references the project.
What happens if I delete an item from a Lookup source list?
It depends on the Cascading delete and Restrict delete settings. With Restrict Delete on, SharePoint blocks deletion of source items that are referenced elsewhere. With Cascading Delete on, deleting a source item deletes all dependent items (use with extreme caution — it’s irreversible). With neither on (the default), source items can be deleted and the references become orphaned.