Which AI chatbots can handle PDF files? Main platforms, usage limits, and real workflow differences

AI chatbots are now able to process and analyze PDF files directly in chat. Not all chatbots offer the same PDF capabilities, and each platform has its own unique limits and workflow.

ChatGPT by OpenAI offers advanced PDF handling in its latest versions.

ChatGPT stands out for its flexibility and very high file upload limits. In versions GPT-4o, o3, o3-pro, and o4-mini (Plus, Team, Pro, Enterprise plans), you can upload PDFs up to 512 MB per file, with a ceiling of 2 million tokens per document. Uploading is done via the “attach” icon both on the web and mobile, or through integration with Google Drive and OneDrive.

For those using the free plan, the situation has changed since June 2025: GPT-4o is offered, allowing up to 3 PDF uploads per day, with advanced features only available for those messages. After exceeding the daily limit, the system switches to GPT-4.1 mini, which maintains PDF upload but with stricter limits. GPT-3.5, meanwhile, is no longer available in the free ChatGPT interface but remains active via API for developers and third-party tools.

An important point is that, except in the Enterprise plan, ChatGPT extracts only digital text from PDFs: images, bitmap charts, and scanned tables are not read. Only Enterprise users can access the Visual Retrieval feature, which enables recognition of images, charts, and even signatures inside documents.

The “Projects” workspace allows you to upload up to 20 files (Plus) or 40 files (Pro/Team) and work on multiple documents in a single session. Custom GPTs also let you upload about twenty PDFs as a permanent knowledge base.

ChatGPT’s infrastructure also enables advanced operations such as data extraction, the generation of thematic summaries, comparing different versions of the same file, and creating dynamic reports from multiple PDFs simultaneously. Analysis is handled by processing pipelines that, for example, can export tables, identify recurring entries, or automate content classification by tags or topics.

For users handling high document volumes, OpenAI also offers automation tools via API and native Python functions (available in Plus and higher plans), useful for batch reading and processing PDFs. Security settings ensure uploaded files remain confidential, with customizable retention options for organizations wanting total control over the document lifecycle.

How Claude Opus 4 and Sonnet 4 handle PDF files

The new Claude models, Opus 4 and Sonnet 4, let you upload PDF files up to 32 MB in size and 100 pages per file.

You can upload up to 20 PDFs at once in a single chat or via the API.

These models read all digital text in your PDFs—including headings, tables, and lists—and can answer questions, summarize, and extract data as long as the content is selectable text, not scanned images.

Compared to previous versions, Opus 4 and Sonnet 4 provide better understanding, deeper reasoning, and improved handling of long or complex documents, making it easier to get detailed insights or code from your PDF content.

If your file is larger or contains more pages than the limit, you’ll need to split it before uploading.

Key features are as follows...

• Maximum file size: 32 MB per PDF

• Maximum length: 100 pages per file

• Batch upload: Up to 20 PDFs per session (chat/API)

• Text handling: Reads all digital text, tables, and lists

• No OCR: Cannot process scanned image-only PDFs

• Improved reasoning: Deeper understanding and better answers for complex or long documents

Claude 3.5 and Opus are specialized in PDF and chart analysis, though with tighter size and page limits.

Claude, in Opus, Sonnet, Haiku, and especially the recent 3.5, allows PDF uploads directly in chat or via the Files API (Bedrock). The maximum limit is 32 MB and 100 pages per request, with up to 20 files per thread when working in batch.

Claude is known for its ability to analyze not only text but also document structure, tables, and even charts within digital PDFs.

In business versions, Claude can activate “visual” mode, which adds recognition of graphic elements, but only via API or on Bedrock with citations enabled. The platform provides excellent data extraction tools for reports, technical white papers, and academic documents of small to medium size, as long as the file size threshold is not exceeded.

Claude’s interface is designed to favor semantic search and internal document navigation.

Users can select specific portions of a PDF, ask for explanations of complex sections, or generate thematic summaries—even from groups of related files. Its tabular data analysis is especially advanced, with the ability to return reformatted tables, lists of anomalies, or cross-dataset comparisons within the same document.

From a security standpoint, Claude implements strict privacy and file retention controls, making it suitable for sensitive business document analysis. Integration with cloud platforms and workflow tools enables process automation such as document classification, scheduled report generation, and automatic summary distribution via email or API.

Gemini 2.5 enables PDF upload on web, app, and API, focusing on large-scale workflows.

Gemini (formerly Bard), in the 2.5 Pro and Flash versions, allows PDF uploads both from the site and via API (Vertex AI). The file size limit rises to 50 MB via API, with up to 1,000 pages and the ability to send up to 3,000 files per prompt in batch requests through Vertex AI. If uploading via the website, the file limit drops to 7 MB.

Since February 2025, even free users can upload PDF documents directly in the web app. Gemini excels at handling large batches of documents, making it particularly suitable for invoice archives, monthly reports, administrative documentation, or large-scale batch flows. Integration with Google Drive is perfect for those already working in the Google Workspace environment.

Gemini’s ecosystem is heavily oriented toward automation and team collaboration: users can set up pipelines that monitor cloud folders, automatically process new incoming PDFs, and return reports or extracted data via Google Sheets or BigQuery. Gemini also provides tools to verify source reliability, which is useful when working with large data volumes collected from different departments or external sources.

Gemini’s semantic understanding engine allows you to ask complex questions across entire document sets, filter results by keyword or concept, and generate summary dashboards with direct links to the most relevant sections of uploaded PDFs. This versatility makes it especially valued in enterprise and public administration contexts.

Microsoft Copilot has been updated to support uploads of scanned PDFs, with built-in OCR.

Microsoft Copilot (on the web, Windows 11, Copilot 365, and mobile) lets you upload PDFs up to 512 MB, and since June 2025, it automatically applies OCR to scanned PDFs. This means that documents from scanners or photos can also be read and analyzed, going beyond simple digital text extraction.

Copilot is mainly targeted at the business world and can handle financial reports, contracts, ESG documentation, and very long administrative flows. On Windows 11, thanks to the Desktop Share function, it can access any document open on the computer in real time, expanding analysis to any file currently viewed by the user.

Native integration with Office 365 and OneDrive lets Copilot automate recurring processes, such as intelligent document archiving, meeting minute generation, or automatic filling of Excel sheets from data extracted from PDFs. Its analysis tools also support document segmentation by chapter, full-text search, and custom semantic tagging.

For those operating in regulated sectors, Copilot provides audit logs, advanced permission management, and compliance policy compatibility, making it one of the most secure and customizable tools for AI-driven document management. OCR support for large volumes of scanned PDFs is a major advantage for organizations with legacy archives or mass digitization needs.

Perplexity AI enables fast, multi-model PDF uploads, ideal for cross-comparisons.

Perplexity AI lets you upload PDFs up to 25 MB, with up to 10 files at once (no daily limits on Pro plans). The platform stands out for the ability to query multiple AI models at the same time (GPT-4o, Claude Opus, Gemini 2.5) on the same file, receiving different responses and summaries depending on the request and the capabilities of the chosen model.

It is especially useful for quick research, model comparisons, or summaries of academic articles and medium-sized white papers. For files over 80–100 pages, it may recommend splitting them up.

Perplexity’s architecture is designed to facilitate user collaboration and parallel analysis of large data volumes: each uploaded file can be easily shared within a team or published as a public reference, with versioning and change tracking always available. Its internal search feature lets you quickly isolate tables, paragraphs, or specific data inside very complex PDFs.

Another strength of Perplexity is the ability to export results directly in different formats (text, table, CSV, shareable link) and to integrate its analysis workflows with other platforms via API. Using multiple AI models on the same file makes it easy to compare responses and always select the most suitable output for the question or usage context.

The differences between AI chatbots are seen in upload limits, image processing, and workflow integration.

Users need to consider several key parameters:

• File size: ChatGPT and Copilot accept much larger PDFs (up to 512 MB), while Claude and Gemini cap at 32 MB and 50 MB respectively.

• Number of pages and files per session: Gemini is unbeatable for batch management, while ChatGPT and Copilot are most generous on single file size.

• Image and chart support: Only ChatGPT Enterprise, Claude Opus (visual mode), and Copilot (OCR) can read tables and charts in image format.

• Cost and daily limits: ChatGPT Free and Perplexity Free have strict limits; Pro/Plus/Team plans offer wider thresholds and more features.

• API and automation: Claude and Gemini integrate easily into API workflows; ChatGPT supports advanced automation through Projects, Python, and Custom GPTs.

The variety of available models on each platform allows further customization: fast models for quick analyses, more advanced engines for complex document flows, batch functions for massive loads. The ongoing evolution of OCR and visual recognition features continually expands the range of processable documents, narrowing the gap between digital and paper content.

Privacy and data retention are crucial factors in choosing a chatbot: while all major providers offer solid security guarantees, only some allow granular permission management, customized retention periods, and integration with enterprise governance systems. This is vital for companies subject to strict regulations or handling sensitive data.

PDF handling in AI chatbots is becoming more advanced and customizable.

In 2025, choosing between chatbots mostly depends on the type of document you need to analyze, the need to process images or large volumes, and how the platform integrates with your digital workflow. ChatGPT remains the most flexible for power users, while Gemini is preferable for mass document flows, Claude excels with structured PDFs full of complex data, Copilot stands out for scanned PDF reading, and Perplexity offers a cross-platform solution ideal for research and model comparisons.

The ability to upload and work with PDF files is now one of the main distinguishing factors among AI chatbots, making these platforms increasingly essential tools for productivity and document management.

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