.HEIC file signature
A High Efficiency Image Format file begins with the bytes 66 74 79 70 68 65 69 63 (ftypheic in ASCII) at offset 4 (0x4). The signature is the same whatever the file is named, which is why a renamed or extensionless HEIF file is still recognisable.
Known signatures
| Offset | Hex | ASCII |
|---|---|---|
| 4 | 66 74 79 70 68 65 69 63HEIC (HEVC-coded), the iPhone default. | ftypheic |
| 4 | 66 74 79 70 6D 69 66 31Generic HEIF brand. | ftypmif1 |
MIME type: image/heif · usual extensions: .heic, .heif
How to check a file's signature
Without installing anything: drop the file on our detector. It reads the bytes in your browser and shows the hex dump alongside the verdict; nothing is uploaded.
macOS and Linux (Terminal):
xxd -l 32 file.heic
file file.heicWindows (PowerShell):
Format-Hex -Path file.heic -Count 32This signature sits at offset 4, so look there rather than at the first bytes: xxd -s 4 -l 16 file.heic.
If the bytes do not match
A file named .heic whose first bytes are something else is not a HEIF file. The common explanations are a wrong or deliberately misleading extension, a download that saved an HTML error page instead of the file, or a container such as ZIP wrapping the real content. The detector reports what the bytes say; the HEIF guide explains what a genuine file should contain.