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.iso

What is a .iso file?

ISO is a byte-for-byte disc image — a complete replica of a CD, DVD, or Blu-ray captured in a single file.

Use caution
Type System
By ISO 9660 standard
MIME application/x-iso9660-image

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What is it

You're installing Linux, setting up a Windows recovery drive, or someone sent you a disc image. It's an ISO — a file that contains every byte of an optical disc in a single archive. The format was born from the ISO 9660 standard for CD-ROM data layout, and it outlived the medium it was designed for.

Physical disc drives are vanishing from laptops, but ISOs are everywhere. Linux distributions ship as ISOs. Windows installers come as ISOs. Game preservationists archive ISOs. The file is a bit-perfect copy of the disc — not just the files, but the filesystem structure, boot sectors, and metadata. This is why you can create a bootable USB drive from an ISO but not from a ZIP of the same files.

Both Windows (8+) and macOS can mount ISOs natively — double-click and the file appears as a virtual drive. 7-Zip can extract the contents without mounting. For creating ISOs, Rufus (Windows, free) and Disk Utility (macOS) handle the job. For burning to physical media — if you still have a drive — ImgBurn (Windows) and the built-in macOS burner work fine.

Technical details
Full Name
Disc Image
MIME Type
application/x-iso9660-image
Developer
ISO 9660 standard
Magic Bytes
43 44 30 30 31
Safety
.iso requires caution. ISO files can contain any software. Only mount ISOs from trusted sources.
What opens it
Windows (mounts natively)
FREE Windows 8+
macOS (mounts natively)
FREE macOS
7-Zip
FREE All
FAQ
How do I mount an ISO file?
On Windows 8 and later, double-click the ISO and it mounts as a virtual drive in File Explorer. On macOS, double-click and it mounts in Finder. On Linux, use the ‘mount’ command or your file manager’s built-in mount option.
What is the difference between ISO and IMG?
ISO follows the ISO 9660 filesystem standard used by optical discs. IMG is a more generic disk-image format that can represent hard drives, floppies, or optical discs. For CD/DVD images, they’re often interchangeable. For other disk types, IMG is more flexible.
How do I create an ISO file?
On Windows, use free tools like ImgBurn or PowerISO. On macOS, use Disk Utility (File > New Image > Image from Folder). On Linux, use the ‘genisoimage’ or ‘mkisofs’ command. You can also create an ISO from a physical disc as a backup.
Related formats
.dmg
Apple Disk Image
.img
Disk Image
.bin
Binary File