Grok file upload limits 2026: 150 MB per file, 512 MB in the API

Updated: November 9, 2026

Grok accepts most files up to 150 MB each, and the web app takes about 100 files in one message, according to xAI's Grok FAQ (last updated November 3, 2026). Android allows up to 20 files per message, while iOS supports multiple files without a published number. Developers who send files through the xAI API work with a different ceiling of 512 MB per file, and direct image input in the API is capped at 20 MiB per image.

Grok Bot, xAI's agent product, has its own and more generous rules: 20 attachments per message, 250 MB for documents and audio, 25 MB per image and 1 GB per video. The table below lists every limit xAI publishes today, followed by the supported formats, the rules for large PDFs, the API storage and search costs with a worked example, and the steps to follow when an upload fails.

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Grok surface	Files per message	Size limit per file	Source
grok.com (web)	About 100	150 MB for most files	Grok FAQ
Grok for Android	Up to 20	150 MB for most files	Grok FAQ
Grok for iOS	Multiple, no number published	150 MB for most files	Grok FAQ
Grok Bot desktop app	20	Images 25 MB (200 MB total), documents and audio 250 MB, video 1 GB	Grok Bot docs
xAI Files API	No per-request number published	512 MB	xAI developer docs
xAI Collections	No per-collection number published	100 MB	xAI developer docs
xAI image input	No limit on image count	20 MiB, JPG/JPEG or PNG	xAI developer docs
xAI speech to text	One audio file per request	500 MB	xAI developer docs

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GROK FILE UPLOAD LIMITS ON WEB, ANDROID AND IOS.

The consumer limits apply to grok.com and the Grok mobile apps. xAI's FAQ states that most files, a category it defines as documents, images, code and audio, can be up to 150 MB per file. The number of attachments depends on the client: about 100 files in a single message on the web, up to 20 on Android, and "multiple files" on iOS, where xAI does not give a figure.

xAI adds that limits "can vary slightly by platform or subscription" and that Grok shows an error message when a file goes over a limit. The FAQ does not publish separate file limits for free users and paying subscribers, so the 150 MB figure is the only official per-file number for ordinary chats. Readers who want to compare what each plan costs and how the shared usage pool works can check our guide to Grok pricing and plans.

Size, attachment count and the amount of text the model reads in one answer are three separate constraints. A 120 MB PDF can upload without errors on grok.com, but xAI says very long files may be summarized or handled in sections, so a successful upload does not mean every page enters the answer with the same weight.

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GROK SUPPORTED FILE FORMATS FOR DOCUMENTS, IMAGES, AUDIO AND VIDEO.

The Grok FAQ lists a broad set of formats for the consumer apps, and xAI says the web version often has wider document support than the mobile clients.

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File category	Formats listed by xAI	Notes from xAI
Documents and data	PDF, DOCX, TXT, CSV, XLSX, PPTX, HTML, XML, JSON, MD, LaTeX, ODT, RTF	Web often has wider document support
Code	.py, .cpp, .java, .html, .css and other code files	Uploaded like text documents
Images	JPEG/JPG, PNG, WebP, HEIC, BMP	GIF and SVG support varies by platform
Audio	MP3, WAV, M4A, OGG, FLAC, AAC	Transcription quality can vary
Video	MP4, MOV	Transcription quality can vary

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Mixed uploads are supported, and xAI gives the example of a TXT file, a PDF, a PPTX deck, images and code sent together in one message. For image analysis the FAQ recommends high-resolution images of at least 1000 × 1000 pixels. Spreadsheet users have more specific questions about formulas, sheets and CSV handling, which our guide to Grok spreadsheet uploads covers in detail.

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HOW GROK HANDLES LARGE PDFS AND LONG DOCUMENTS.

For PDFs longer than about 100 pages, xAI says Grok focuses on the text and key visuals, and it recommends referring to specific pages by their actual page numbers when asking about a detail. Embedded images inside files other than PDFs may not be processed visually, so a chart pasted into a DOCX file is less reliable than the same chart in a PDF or uploaded as a separate image.

xAI also advises splitting extremely large documents into smaller parts. A 600-page annual report, for example, gives better answers when it is uploaded as several section files and each question names the section and page range it refers to. For extraction work, asking Grok to return a CSV or JSON table and then checking totals, dates and page references against the original keeps errors visible. Our explainer on whether Grok can read PDFs goes deeper into PDF visuals and document search.

Uploaded files can be managed after the chat ends. On the web, xAI points users to grok.com/files to delete content and free up space, and it says deleted chats and files are removed within standard retention windows unless they must be kept longer for legal, compliance or safety reasons.

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GROK BOT ATTACHMENT LIMITS: 20 FILES, 250 MB DOCUMENTS AND 1 GB VIDEOS.

Grok Bot, xAI's agent product, uses its own attachment table, and its limits are now higher than those of ordinary Grok chats for most file types. The desktop composer accepts 20 attachments per message. Images can be 25 MB each with a total of 200 MB per message, documents, audio and other files can be 250 MB each, and videos can be up to 1 GB each.

Files over a limit are dropped from the composer with a "too large" message, and xAI suggests resending them in a separate message. Grok Bot reads images, audio and video, PDF and plain-text documents, Word, Excel and PowerPoint files, CSV, JSON, YAML, source code, HTML and email files, and Jupyter notebooks. When Grok Bot creates a video, the images it receives must be JPEG, PNG or WebP, and all images for one clip can total about 35 MB. These figures apply only to Grok Bot and should not be used for grok.com chats or for the API.

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XAI API FILE LIMITS: FILES API, COLLECTIONS, IMAGES AND AUDIO.

The xAI Files API accepts files of up to 512 MB each. xAI lists plain text, Markdown, code files, CSV, JSON and PDF, plus "many other text-based formats". Files are stored permanently until deleted, or they can be given an expiration time between 1 hour and 30 days, after which they are removed automatically. Files can be referenced by uploaded file ID or by public URL, and their context persists across conversation turns.

Attaching a file to a request requires a model with agentic tool calling, and xAI names grok-4.20, grok-4.5, grok-4.6 and grok-4.7 as examples. When a file is attached, the model searches it with a document-search tool, and these requests cannot use batch mode with more than one completion (n > 1).

Collections, the API feature for persistent searchable knowledge bases, has a lower ceiling of 100 MB per file and accepts any UTF-8 text file, including PDF, DOCX, XLSX, PPTX, HTML, CSV, JSON and Markdown. xAI says Collections limits can be raised by contacting the company, and that uploading files requires credits in the account.

Two other API inputs have separate rules. Image understanding accepts JPG/JPEG and PNG files up to 20 MiB each, with no cap on the number of images in a request. Speech to text accepts audio files up to 500 MB in formats that include WAV, MP3, OGG, Opus, FLAC, AAC, MP4, M4A, MKV, WebM, AVI and MOV.

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XAI FILE STORAGE AND SEARCH COSTS WITH A WORKED EXAMPLE.

File handling in the API is billed on top of normal token costs. xAI's pricing page lists the following rates.

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xAI API item	Official price
File storage	$0.025 per GiB per day
Collection storage	$0.10 per GiB per day
File attachment search (attachment_search)	$5 per 1,000 calls
Collections search (collections_search / file_search)	$2.50 per 1,000 calls

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Each search the model runs counts as one call, so a single question can trigger more than one billed search. As an example, a team keeps 20 GiB of documents for 30 days and runs 10,000 searches in that month. With the Files API, storage costs 20 × $0.025 × 30 = $15 and searches cost 10 × $5 = $50, for a total of $65. With Collections, storage costs 20 × $0.10 × 30 = $60 and searches cost 10 × $2.50 = $25, for a total of $85.

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20 GiB for 30 days, 10,000 searches	Storage	Search	Total
Files API with attachments	$15	$50	$65
Collections	$60	$25	$85

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Collections storage costs $45 more in this example, while each 1,000 searches costs $2.50 less, so the two options cost the same at 18,000 searches a month. Below that volume, attaching files is cheaper for this amount of data; above it, Collections becomes the cheaper choice as well as the one designed for reusable knowledge bases. Token costs for the model's input and output come on top of both totals.

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WHY A GROK FILE UPLOAD FAILS AND HOW TO FIX IT.

Size is only one cause of a failed upload. xAI lists large, encrypted, damaged or unusual files as possible problems, and GIF and SVG images may succeed on one platform and fail on another. A file that is under the limit can also fail if the upload is interrupted before Grok confirms it.

The fixes are practical. xAI recommends exporting an unusual file as a PDF, CSV, plain text or a standard image format, removing the password from a protected PDF avoids encryption errors, and splitting a very large document into sections helps both the upload and the quality of the answer. On Android, a batch of more than 20 files has to be sent across several messages, and on Grok Bot any file dropped from the composer can be resent on its own.

To upload, click or tap the + icon next to the message box, choose the files and wait for Grok to confirm the upload before asking the question. On the web, deleting old files at grok.com/files frees storage space.

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GROK FILE UPLOAD LIMITS: WHICH NUMBER APPLIES TO YOUR WORKFLOW.

For ordinary chats on grok.com and the mobile apps, the working ceiling is 150 MB per file, with about 100 attachments per message on the web and 20 on Android. Grok Bot users get 20 attachments with larger caps for documents, audio and video, and developers work with 512 MB per file in the Files API, 100 MB per file in Collections, 20 MiB per image and 500 MB per audio file.

The points xAI leaves open are plan differences and iOS attachment counts. The FAQ says limits can vary by subscription without listing them, and it gives no number for iOS, so anyone building a workflow around an exact cap should test it on the platform and plan they use. A process that moves between grok.com, Grok Bot and the API should store a separate limit for each surface instead of one Grok-wide file-size constant.

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