2-4-file-upload

--- title: "Uploading Files to Claude: Analyze PDFs, Images, Code and Data" description: "Claude can read and analyze documents, images, source code and CSV files. Discover what it supports, how it works and how to get the most from file analysis." slug: "2-4-file-upload" enslug: "2-4-uploading-files-to-claude" accesslevel: registered status: published visible: true featured: false priority: 24 date: 2026-04-22 updated: 2026-04-22 author: "Dario Santocanale" reading_time: "8 min" prerequisites: - Having completed Cluster 1 tutorials tags: [claude, file, pdf, images, analysis, advanced, upload] ---

Many of Claude's most useful features unlock when you stop pasting text and start uploading files directly. Here's what you can do.

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Supported file types

Type	Formats	What Claude does
Documents	PDF, Word (.docx), TXT	Reads, summarizes, analyzes, answers questions
Images	JPG, PNG, GIF, WebP	Describes, analyzes content, reads text (OCR), interprets charts
Code	.py, .js, .ts, .php, .html, .css, ...	Analyzes, finds bugs, explains, refactors
Data	CSV, TXT with tabular data	Analyzes patterns, calculates statistics, suggests visualizations
Spreadsheets	Excel (.xlsx) — limited	Reads basic structure

Note: Claude doesn't support audio or video files directly in chat.

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How to upload a file

1. In the chat, click the paperclip icon (📎) in the message bar
2. Select the file from your computer
3. Wait for the upload (a progress bar appears)
4. Write your prompt in the same text box
5. Send

You can upload multiple files in the same message — hold Ctrl (or Cmd on Mac) to select multiple.

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PDF analysis: the most common use case

PDF is the most commonly uploaded format. Practical uses:

Contracts and legal documents

Analyze this contract. Identify:
1. Problematic or unusual clauses
2. Main obligations for each party
3. Termination conditions
4. Any ambiguous terms that should be clarified
Use plain language, not legal jargon.

Financial reports

This is the annual report for [company]. 
Summarize the main KPIs in a markdown table.
Then tell me the 3 most concerning signals and the 3 most positive ones.

Scientific papers

Read this paper. Explain to me:
- The problem it solves (in 2 sentences)
- The method used (without formulas)
- The main results
- Why it matters for [my field]
Explanation level: I'm not an expert in this field.

CVs and job applications

This is a candidate's CV for a [position] role.
Our main requirements are: [list].
Tell me: 1) Fit with requirements (0-10 with explanation)
2) Strengths
3) Main gaps
4) Questions to ask in the interview

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Image analysis

Claude "sees" images — not just describes them, but interprets them.

UI screenshots / bugs

This is a screenshot of my application.
The reported bug is that the "Save" button isn't visible on mobile.
From the image, can you see the problem? Suggest the cause.

Charts and infographics

This is a chart of sales data.
Describe the trend, identify anomalies and tell me what this chart 
would communicate well to a CEO who doesn't have time for details.

Photos of physical documents

If you have a paper document, photograph it and upload the photo. Claude can read the text (built-in OCR) and analyze it like a PDF.

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CSV data analysis

For quick tabular data analysis without opening Excel:

This CSV contains sales data for the last 12 months.
Columns: date, product, quantity, revenue, region.
Tell me:
1. The product with the highest total revenue
2. The region with the greatest month-over-month growth
3. Whether there are obvious outliers or anomalies
4. A SQL query that would replicate the same analysis

Important limitation: Claude doesn't execute mathematical calculations on large datasets like Python/Excel would. It interprets and suggests, but might make errors on sums and averages with very large data. For precise numerical analysis, use dedicated tools.

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Source code analysis

Upload code files for review, debugging or documentation:

Analyze this PHP file. Look for:
1. Security vulnerabilities (SQL injection, XSS, etc.)
2. Obvious performance issues
3. Code sections that could benefit from refactoring
4. Undocumented functions (add PHPDoc)
Prioritize by impact.

You can upload multiple code files together for cross-file analysis:

I've uploaded 3 files from my project: Controller, Model and View.
Analyze how they interact and tell me if there's separation of concerns
or if the Controller is doing too many things.

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Document comparison

One of the most powerful features: uploading two files and comparing them.

I've uploaded the original and revised version of the same document.
Identify all significant differences.
Then tell me if the changes improve clarity and coherence.

These are two supply contracts from different vendors.
Compare them on: price, payment terms, warranties,
penalties and withdrawal conditions.
Create a comparison table and tell me which is more advantageous
considering our priority is flexibility.

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Files in Projects: the difference from chat upload

	Upload in chat	Files in Projects
Duration	Only in current conversation	Permanent in the project
Accessible from	1 conversation	All project conversations
Size limit	Per single file	Project total
Ideal use	One-shot analysis	Recurring reference documents

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File upload limitations

• Maximum size per file: ~25 MB for PDFs, ~5 MB for images
• PDFs with scanned images (not real text) are read worse than those with actual text
• Very long files: Claude might only read the first X tokens if they exceed the window
• Doesn't support .zip, .exe, audio, video files

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