Claude Opus 4.5 file upload and reading: supported formats, size limits, and practical workflow features

Claude Opus 4.5 maintains robust file upload and document reading capabilities, supporting advanced document workflows and multi-step analysis for a wide range of formats.

The model’s ability to process large, structured files and interpret their content is essential for users who rely on document summarization, data extraction, and project review within a single chat session.

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File upload in Claude Opus 4.5 supports a broad range of standard document types.

Users can upload files directly into the chat interface, where Claude extracts, tokenizes, and interprets text from each document.

Supported formats include PDFs (including multipage and scanned), Word documents, spreadsheets, images with embedded text (OCR), and plain code files.

The system is designed to handle most business, academic, and technical document types without requiring manual conversion.

Uploads are processed entirely within the conversation’s context window, so very large documents may require summarization or chunking.

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Supported file types in Claude Opus 4.5

File type	Example extensions	Typical use cases
PDF	.pdf	Summaries, structured analysis
Word	.doc, .docx	Reading, extraction
Spreadsheet	.csv, .xlsx	Table analysis, calculations
Image (OCR)	.png, .jpg	Extracting text from images
Code	.py, .js, .txt, .md	Parsing, explanation, review

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Claude Opus 4.5 enforces upload limits for file size and total document count.

To ensure smooth operation and context management, each uploaded file must not exceed 30 MB.

A maximum of 20 files can be uploaded per chat session.

Total content is further limited by the model’s context window, which determines how much of the extracted text is processed at once.

When uploading several large files, users may need to work iteratively or request summaries to fit within these boundaries.

These limits are consistent across all Claude 4.5 model tiers and are enforced at the platform level.

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File upload limits in Claude Opus 4.5

Upload constraint	Limit
Maximum file size	30 MB
Maximum files/chat	20
Processing scope	Model context window (tokens)

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Document reading and extraction rely on context-aware processing and advanced reasoning.

When a file is uploaded, Claude performs automatic text extraction, including OCR for images, and processes the content within the active chat.

The model can summarize long reports, extract tables or code, identify recurring patterns, and answer specific questions about document content.

Each referenced file is re-read as needed in multi-turn conversations, allowing users to revisit and cross-compare different documents within the same session.

The advanced context handling in Opus 4.5 ensures stable performance even with complex, mixed-format workflows.

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Key document reading and workflow features

Capability	Description
Automatic text extraction	Text and tables from files and images
Multi-file comparison	Cross-analysis within the same session
Summarization	High-level overviews for long documents
Structured extraction	Tables, code, and key insights from uploads
Iterative review	Ongoing reference to files across multiple turns

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Advanced reasoning in Opus 4.5 improves real-world file analysis and multi-document workflows.

While file upload is a core platform feature, Opus 4.5’s reasoning and memory improvements enhance performance on extended projects.

The model is optimized for persistent context, structured information extraction, and combining evidence from several sources.

This allows for more reliable document review, complex analytical tasks, and deeper summarization than prior model generations.

Opus 4.5 supports use cases that require reading, comparing, and synthesizing content from diverse files in a single workflow, benefiting both professional and research-oriented users.

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