xAI has released a Grok add-in for Excel, available on the Microsoft Marketplace, which places a sidebar in the spreadsheet application to "search the web, update spreadsheets, or build powerful financial models." The add-in itself is free, but it is currently available only for SuperGrok, Heavy, Business, and Enterprise plans. The level of integration is lower than Microsoft's Copilot, which in 2025 announced a function allowing users to invoke its assistant at the workbook cell level. Microsoft warns that the app "can read and make changes to your document, can send data over the internet." When tested with a request to "create a chart showing SpaceX stock performance since IPO," Grok said it had reached usage limits and suggested upgrading the plan; simpler requests also failed, confirming a subscription is required. Grok, which hit version 4.5 this month, was claimed by xAI to be "capable of building complex Excel models," though Grok Build was previously caught sending entire repositories to the cloud.