ATR File

What are ATR files and how to open them

Are you having problems opening an ATR file or are you simply curious about its contents? We're here to explain the properties of these files and provide you with software that can open or handle your ATR files.

What is an ATR file?

An .ATR file is an Atari ATR Disk Image file.

Atari ATR Disk Image files store a complete copy of a floppy-disk used by the 8-bit Atari family, including all user data sectors plus boot and directory structures. They act as exact binary snapshots of Atari floppies, so that disk operations can be emulated or restored without the original drive hardware. Invented for the SIO2PC project by Nick Kennedy, they are broadly supported by Atari emulators and tools.

These images are produced by reading an Atari 8-bit floppy disk sector by sector, then writing the data into a file with a 16-byte header describing disk geometry (sector size, image size, flags, etc.). After creation, they are used by emulators or disk-manipulation utilities to read files from or write files to the disk image just like a physical disk. Formats based on this are used for backing up disks, distributing disk-based programs, or preserving software.

Files start with a fixed two-byte "magic number" signature, followed by fields that include image size in "paragraphs" (16-byte units), sector size (typically 128 or 256 bytes), and other flags. The signature is the bytes 0x96 0x02 at offset zero.

How to open ATR files

Important: Different programs may use files with the ATR file extension for different purposes, so unless you are sure which format your ATR file is, you may need to try a few different programs.

While we have not verified the apps ourselves yet, our users have suggested five different ATR openers which you will find listed below.

Last updated: August 22, 2026

Various apps that use files with this extension

These apps are known to open certain types of ATR files. Remember, different programs may use ATR files for different purposes, so you may need to try out a few of them to be able to open your specific file.

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File.org helps thousands of users every day, and we would love to hear from you if you have additional information about ATR file formats, example files, or compatible programs. Please use the links below or email us at submit@file.org to discuss further.