The Microsoft Copilot file upload limit is 50 MB per file, with up to 20 files in a single conversation, according to Microsoft Support’s File upload in Microsoft Copilot article.
As of November 10, 2026, Microsoft says these limits apply to all Microsoft Copilot experiences: personal accounts (Personal, Family, Premium and Pro), work or school accounts, and free Copilot Chat. Supported upload formats are PDF, DOCX, XLSX and PPTX documents; PNG, JPEG, PJP and JFIF images; and TXT, TEXT, JSON, CSV and MD files. If a conversation already has 20 files, start a new conversation to add more.
Microsoft says uploaded files are stored for no longer than 18 months and are not used for model training. Agent builders in Copilot Studio work with a separate limit of 512 MB per uploaded file and 500 uploaded files, per the Copilot Studio quotas and limits page on Microsoft Learn.
Related: How much does Microsoft Copilot cost?, Does Microsoft Copilot train on your data? and What is the ChatGPT file upload limit?
Source: Microsoft Support, File upload in Microsoft Copilot and Microsoft Learn, Quotas and limits for Microsoft Copilot Studio
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