What Is a .pdf File? .pdf Format, MIME & How to Open

Quick facts

Extension.pdf

File typePDF Document

MIME typeapplication/pdf

CategoryDocument

Charset—

CompressibleNo

Format familypdf

What is .pdf

What is a .pdf file?

A .pdf file is a PDF Document — Portable Document Format for fixed-layout documents across platforms.

In the mime-db registry it maps to application/pdf, and it is marked as non-compressible. When serving .pdf over HTTP, set the Content-Type header as shown in Developer info below.

Related entities: it maps to application/pdf — and is delivered over HTTP via the Content-Type header.

How to open .pdf files

Use Adobe Acrobat or Chrome to open and edit .pdf files.
Any text editor (Notepad, VS Code) can inspect the raw content as text.

Developer info

When served over HTTP, responses should set the following header:

Content-Type: application/pdf

Common software that reads/writes .pdf:

Adobe AcrobatChromePreviewLibreOffice

Relation chain

.pdfextension of

format

pdfserved as

mime type

application/pdfsent via header

http header

Related extensions

Related MIME types

Common uses

Reports and letters
Spreadsheets and budgets
Presentations
Ebooks

How to edit .pdf files

Open the file with Adobe Acrobat, make your changes and save.
Most editors preserve the original formatting and encoding — avoid changing the charset.

How to create .pdf files

Create a new file and save it with the .pdf extension, or export this format from Adobe Acrobat.

Frequently asked questions

What programs can open .pdf files?

Common options include Adobe Acrobat, Chrome, Preview. You can also open many of these files with built-in viewers or a browser.

How do I create a .pdf file?

Create a new file in any text editor or the app that owns the format and save it with the .pdf extension.

What is the relationship between .pdf and the application/pdf MIME type?

application/pdf is the media type identifier used for .pdf files during network transfer (for example in the HTTP Content-Type header).

Sources & standards

Updated 2026-09-13

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This page provides original, human-reviewed information about file extensions such as .pdf, the File Extension Reference and related concepts. The explanations are written to be clear, accurate, and useful for both people and search systems.

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