Claude Upload Limit: File Size, PDFs and API Caps

The Claude upload limit in a chat is 500MB per file and up to 20 files per chat, according to Anthropic's Upload files to Claude help article. Files you add to a Project are capped lower, at 30MB per file. PDFs over 1,000 pages can't be uploaded at all, and Claude only looks at charts and images in PDFs of 100 pages or fewer.

Those are the headline numbers. But the limit that stops most people isn't file size. It's the context window, which is how much text Claude can hold in one conversation. A 40MB PDF can upload fine and still be too long for Claude to read in one go.

Here's the full picture:

• Chat uploads: 500MB per file, 20 files per chat, images up to 8000x8000 pixels
• Project files: 30MB per file, unlimited count, but the total has to fit the context window
• PDFs: 1,000 pages max; full visual analysis up to 100 pages, text only above that
• API: 32MB per Messages request, 500MB per file through the Files API
• The real ceiling: the context window, plus your plan's usage limits

Every figure below comes from Anthropic's own help center or developer docs. They change, so the linked pages are the source to trust on the day you check.

Claude File Upload Limits at a Glance

That third row needs a word of explanation. Anthropic's create and edit files article says "The maximum file size is 30MB per file for both uploads and downloads" for the code execution feature. The main upload article says 500MB for chat uploads. The two pages don't explain the difference. A safe reading: when Claude is working on a file inside its code environment, plan for 30MB. For a plain chat attachment, 500MB is the published cap.

Supported file types

Claude accepts PDF, DOCX, CSV, TXT, HTML, ODT, RTF, EPUB, JSON and XLSX documents, plus JPEG, PNG, GIF and WebP images. XLSX is the odd one out: you have to turn on code execution and file creation before Claude will take a spreadsheet.

For everything that isn't a PDF, Claude extracts the text only. If your Word file has a chart pasted in, Claude won't see it.

Claude Projects Upload Limit

Projects work differently from a single chat. Per Anthropic, project files are capped at 30MB per file, and the number of files is unlimited, "but total content must fit within Claude's context window."

Two other details matter:

• Text extraction only. Project files are read as text, except for multimodal PDFs.
• Caching helps your usage. Anthropic's usage limit best practices says content in projects is cached and "counts less against your limits when reused." If you ask ten questions about the same report, keeping it in a project beats re-uploading it ten times.

On paid plans, Projects also switch to retrieval (RAG) automatically when a project approaches the context window limit. Claude then searches your files and pulls in only the most relevant parts, which Anthropic says can expand a project's capacity by up to 10x. If you're deciding between Projects and similar features elsewhere, we compared them in Claude Projects vs Custom GPTs.

Claude PDF Limits: Pages, Size and Visual Analysis

PDFs get their own rules because Claude can read them two ways: as text, or as text plus page images.

So a 300-page annual report uploads fine, but Claude won't read its charts. If the charts are the point, split out the pages you need into a smaller PDF first.

One practical tip from Anthropic: when you refer to a page, use the page number your PDF viewer shows, not the number printed on the page itself. Front matter throws those off.

For a deeper look at what Claude does with PDFs, including scanned files and tables, see can Claude read PDFs.

Claude Image Upload Limits

In chat, images can be up to 8000x8000 pixels. Anthropic's vision documentation adds two claude.ai limits: 20 images per message and 10MB per image.

Bigger isn't always better here. Claude downscales large images before processing, and the help article recommends images of at least 1000x1000 pixels. Very small or low-resolution images are where Claude makes mistakes.

Claude API Upload Limits and the Files API

If you're building on the API, the caps are different and stricter per request.

Anthropic's API overview lists these request size limits:

Go over and you get a 413 request_too_large error. Partner platforms set their own caps: the same page says Bedrock limits requests to 20MB and Claude Models on Google Cloud (Google managed) to 30MB.

The Files API is the fix for big documents. You upload a file once, then reference it by file_id instead of stuffing it into every request. Its limits:

• 500MB per file
• 1TB of total storage per organization
• About 500 requests per minute for file-related calls

PDFs have their own API rules. Anthropic's PDF support page sets a maximum of 600 pages per request, or 100 when the request's context window is under 1M tokens. Each page typically uses 1,500 to 3,000 tokens of text, and pages are also processed as images. The docs warn that dense PDFs "can fill the context window before reaching the page limit."

Images on the API follow a similar pattern: up to 600 per request (100 on 200k-context models), 8000x8000 pixels each, and 10MB per image base64-encoded. Once a request carries more than 20 images, a stricter per-image size kicks in, so keeping each image under 2000px on both sides is the safe default.

The Real Ceiling: Claude's Length Limit and Context Window

Here's the part most upload-limit guides skip. A file can pass every size check and still fail, because what Claude actually reads is tokens, not megabytes.

Anthropic's help article on usage and length limits puts it this way: length limits relate to the context window, "the amount of information Claude can work with in a single chat." On paid plans, "the newest models support up to a 1M token context window, while others support 500K or 200K tokens." Part of that window is always held back for Claude's reply.

Everything you attach counts against that window. So does the conversation so far. That's why a long chat with several big attachments eventually shows "Your message will exceed the length limit for this chat," which Anthropic's error troubleshooting article pairs with a suggestion to attach fewer or smaller files or start a new conversation. If you want the mechanics behind this, our explainer on the context window covers how tokens add up.

With code execution turned on, you get some relief: when a conversation nears the limit, Claude summarizes earlier messages so it can keep going. Anthropic notes that those longer conversations use more of your usage limit.

How to Get Around Claude's Upload Limits

When a file is too big or too long, these fixes work, roughly in the order you should try them:

1. Split the document. Anthropic's own advice for large files is to divide them into smaller sections. Split a 1,400-page PDF into two parts, or pull out only the chapters you need.
2. Extract the text. If you don't need the visuals, save or export the document as plain text. Text is far smaller in tokens than page images, and it skips the 100-page visual cutoff entirely.
3. Convert the format. A slide deck exported to PDF keeps its visuals. A spreadsheet exported to CSV drops formatting Claude doesn't need.
4. Shrink the images. Downsample embedded images in big PDFs. The API docs suggest this for large files, since each page is processed as an image.
5. Use a Project for repeat work. Files you reuse get cached, and on paid plans retrieval loads only the relevant parts once a project gets large.
6. On the API, use the Files API. Upload once, reference by ID, and keep each request under the 32MB cap.

Upload Limits vs Claude Usage Limits

People often mix these up, so briefly:

• Upload limits are about one file or one request: size, page count, number of files.
• Usage limits are about how much you use Claude over time. Paid plans have a session limit that resets every five hours and weekly limits that reset once a week.

They do interact. Anthropic's usage limit best practices list the size of files you attach among the factors that affect your usage, so a 500-page PDF uses up your allowance much faster than a short question.

What Anthropic doesn't publish is an exact message count for any plan. The number you can send depends on message length, attachments, conversation length, the model and the features you use. Usage across claude.ai, Claude Code and Claude Desktop counts toward the same limit. If you're hitting usage limits rather than upload limits, the question is which plan fits. We compare the paid tiers in Claude Max vs Pro.

FAQ

What is the Claude file upload limit?

In a chat, 500MB per file and up to 20 files per chat, per Anthropic's help center. Project files are limited to 30MB each. PDFs over 1,000 pages can't be uploaded.

What is the Claude Projects upload limit?

30MB per file. You can add unlimited files, but the total content must fit within Claude's context window.

How many pages can Claude read in a PDF?

Up to 1,000 pages in the Claude app. It analyzes text and visuals up to 100 pages, and text only from 101 to 1,000. On the API, a single request can include up to 600 PDF pages, or 100 when the context window is under 1M tokens.

Why does Claude say my file is too large when it's under 500MB?

Usually it's one of three things: the PDF is over 1,000 pages, the extracted text is too long for the context window, or you're using a feature with a lower cap, such as Projects or code execution at 30MB. Splitting the file fixes all three.

Does the Claude free plan have a lower upload limit?

Anthropic's upload article doesn't list separate file limits by plan. Plans differ in usage limits, which control how much you can do over time, not how big a single file can be.

What is Claude's message limit?

Anthropic doesn't publish a fixed number. Your allowance depends on message length, attachments, conversation length, model and features, and paid plans reset on a five-hour session and a weekly cycle. You can see your progress in Settings > Usage on paid plans.

What is the Claude API file size limit?

32MB per Messages request, 256MB per Message Batches request, and 500MB per file through the Files API, with 1TB of storage per organization.

Key Takeaways

• Chat: 500MB per file, 20 files per chat, images up to 8000x8000 pixels.
• Projects: 30MB per file, unlimited count, bounded by the context window.
• PDFs: 1,000 pages max, with visual analysis only up to 100 pages.
• API: 32MB per request; use the Files API (500MB per file) for anything large.
• The real limit is the context window. Split, extract text or convert before you upload.

If you keep re-uploading the same files to redo the same analysis, the bottleneck is the workflow, not the file size. Taku is an AI-native desktop workspace where a setup that worked once stays saved, so you can run it again on next month's files instead of starting from a blank chat. Taku is in Beta, and the Mac app is available now.