Microsoft Copilot File Upload and Reading: supported formats, limits, and enterprise behavior

Microsoft Copilot integrates document interpretation across Microsoft 365, web chat, and custom agent environments, enabling users to upload, read, and analyze files within the same workspace. From PDF summaries to spreadsheet reasoning and PowerPoint analysis, Copilot’s document processing relies on Microsoft Graph and adheres to organizational data governance. As of late 2025, file upload capabilities vary across platforms, with defined size limits, storage locations, and compliance policies that determine how files are processed, stored, and secured.

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File uploads in Copilot Chat and Microsoft 365 apps.

In the Microsoft 365 Copilot Chat interface, users can upload files directly into the conversation by selecting “Add content” or dragging and dropping the file. Once uploaded, Copilot can summarize, extract tables, analyze data, and answer questions about content in Word, Excel, PowerPoint, or PDF documents.

Supported file types include PDF, DOC, DOCX, XLS, XLSX, PPT, and PPTX, along with image formats for visual interpretation. After upload, users can issue structured prompts such as “Summarize this file,” “Extract key figures from page 5,” or “Convert this data into a table.” The document is then processed through Microsoft Graph, allowing Copilot to ground its reasoning in authenticated enterprise data.

In Word, Excel, and PowerPoint, Copilot operates directly within the document context, without requiring file attachment. For instance:

• In Word, it can review and summarize open files, generate outlines, or rewrite selected paragraphs.

• In Excel, it can identify trends, calculate statistics, and generate charts.

• In PowerPoint, it can explain slide data, suggest speaker notes, or create new slides from source files.

For Teams and Outlook, Copilot can summarize conversations, attachments, and meeting notes, but it does not summarize or interpret images or Loop components directly from chat threads. Documents shared within Teams must be opened in their respective apps to enable Copilot reasoning.

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File upload in Copilot Studio and custom agents.

Copilot Studio, Microsoft’s environment for creating custom copilots, extends file reading into enterprise development. Builders can upload knowledge files—such as PDF, DOCX, HTML, or TXT documents—to serve as reference material for their agent. These files are processed into a Dataverse knowledge base that supports the Generative Answers feature.

In Studio, each uploaded document can be up to 512 MB, and each custom copilot can include up to 500 files, constrained only by the organization’s Dataverse storage capacity. Unlike Copilot Chat, Copilot Studio does not support image, audio, video, or executable file uploads. Instead, it focuses on text-centric knowledge ingestion, where documents are embedded and indexed for retrieval-grounded responses.

This makes Copilot Studio suitable for building domain-specific assistants—such as HR, legal, or finance copilots—that answer questions using internal policy or training documents.

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File size limits and usage boundaries.

Microsoft does not define a single global upload limit across all Copilot surfaces; limits are tenant-specific and can vary depending on the organization’s licensing and administrative settings. However, several consistent guidelines are documented:

• Copilot Chat: Enterprise administrators often enforce upload limits between 1 MB and 10 MB, depending on tenant configuration. Files larger than this should be stored in SharePoint or OneDrive and opened directly within Word or Excel for processing.

• File content guidance: For reliable summarization, Microsoft suggests keeping document content under approximately 1.5 million words or 300 pages. For rewriting and draft generation, files under 3,000 words yield faster and more coherent results.

• Copilot Studio: Each file can be up to 512 MB, with cumulative limits tied to Dataverse storage capacity. This enables ingestion of larger reference datasets for persistent knowledge retrieval.

These guidelines ensure that Copilot operates efficiently, maintaining response times and accuracy within predictable resource boundaries.

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Where uploaded files are stored.

When a file is uploaded to Copilot Chat (work or school accounts), it is automatically stored in the user’s OneDrive under a dedicated folder named “Microsoft Copilot Chat Files.” This folder falls under the same retention, eDiscovery, and compliance policies as other organizational OneDrive data. Administrators can apply labels, holds, or governance rules through Microsoft Purview and standard data retention tools.

In Copilot Studio, files uploaded as knowledge sources are stored within Microsoft Dataverse. These files count toward the environment’s allocated capacity and are governed by Power Platform’s retention and access controls. Because files stored in Dataverse can serve multiple agents or flows, they remain available for subsequent updates or re-indexing without repeated uploads.

This approach ensures that files processed through Copilot remain within the organization’s compliance perimeter while preserving traceability for auditing and discovery.

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Security, permissions, and data boundaries.

All file handling in Copilot is governed by Microsoft Graph permissions. Copilot only retrieves and summarizes content that the signed-in user is already authorized to access. Files inherit their original access controls from SharePoint, OneDrive, or Teams, and any document protected by encryption or sensitivity labels maintains those restrictions during Copilot analysis.

Data residency follows the organization’s Preferred Data Location (PDL) or Primary Provisioned Geography, ensuring uploaded files and interaction data remain in-region under Multi-Geo configurations. Within Microsoft 365 workloads, data remains inside the Microsoft Cloud trust boundary and is not shared externally.

For organizations that deploy third-party connectors or Copilot extensions, Microsoft clearly distinguishes between in-tenant grounding and external integrations. Only plugins explicitly enabled by the administrator may send limited data outside of this boundary for processing.

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Table — Microsoft Copilot file upload and reading capabilities by platform.

Environment	Supported File Types	Max File Size / Limit	Storage Location	Notes
Copilot Chat (Microsoft 365)	PDF, DOCX, XLSX, PPTX, images	Tenant-specific (≈1–10 MB typical)	OneDrive → Microsoft Copilot Chat Files	Full Q&A and summarization grounded in Microsoft Graph
Copilot (consumer web)	Documents and images	No universal cap published	User’s Microsoft account storage	For personal chat analysis
Word, Excel, PowerPoint Copilot	Active document context	Based on open file size limits	Stored in M365 apps or OneDrive	Direct in-app reasoning
Copilot Studio (custom agents)	PDF, DOCX, TXT, HTML	512 MB per file; up to 500 files	Dataverse	Used as long-term knowledge base
Teams Copilot	Conversations only (no file summaries in-thread)	—	Teams/SharePoint	Files must be opened in apps to analyze

This table summarizes the operational boundaries for file reading and upload across Microsoft’s Copilot ecosystem.

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Governance and compliance best practices.

• Audit uploads regularly: Files saved in the “Copilot Chat Files” folder should be subject to existing retention and eDiscovery policies.

• Use app-level Copilot for large documents: When file size exceeds chat limits, open it directly in Word or Excel and use Copilot’s in-app reasoning to avoid truncation.

• Define data residency: Verify that uploaded file processing aligns with organizational data location policies under Multi-Geo settings.

• Limit plugin access: Only enable third-party connectors when necessary, as these may transmit data outside the Microsoft cloud boundary.

• Centralize long-term corpora: Use Copilot Studio for institutional knowledge, with clear governance for Dataverse storage and document versioning.

Adhering to these controls maintains both performance and compliance integrity across Copilot workloads.

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Summary of Microsoft Copilot’s document capabilities.

Microsoft Copilot’s file upload and reading framework bridges ad-hoc document chat, in-app editing, and enterprise-scale knowledge ingestion. Users can upload and query PDFs, spreadsheets, and presentations within Copilot Chat, while developers and organizations can integrate structured document repositories through Copilot Studio.

Uploads are automatically stored in secure, compliant locations—OneDrive for individual chat sessions and Dataverse for persistent agents. File size and processing limits vary by tenant configuration, but security remains consistent through Microsoft Graph permission trimming and regional data controls.

In 2025, Copilot’s document intelligence ecosystem provides a unified framework for grounded reasoning, combining accessibility, compliance, and enterprise control under one architecture.

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