Live data

Build Number
Decoder

Enter any Apple firmware build string and instantly decode its iOS version, platform, signing status, file size and compatible devices — all from live data.

firmware_decode.sh api connected
Format: MajorMinorPatchVariant
23D8133 22C160 21A326 20H115 19H12 18G82

Build not found.

Anatomy

How Apple build numbers work.

Every Apple firmware build follows the same structure. Once you know the pattern you can read any build string at a glance.

build_anatomy.sh — example: 22C160
22Major
CMinor
1Patch
60Build
Major — the number prefix
Maps to the OS major version. 22 = iOS 18 (iOS major + 4 since iOS 10). Shared across iOS, iPadOS, macOS, watchOS of the same year.
Minor — the letter
A = first release of the year (.0), B = second (.1), C = third (.2), and so on. Resets with each major OS version.
Patch — incremental revision
Increments for each new build within a minor release cycle. Zero or absent means the first build of that minor.
Build variant — the trailing number
Identifies the specific build or device family variant. Different devices occasionally get different build numbers for the same iOS version.
Why build numbers matter

Two devices can both show "iOS 18.2" but carry different build strings — meaning different kernel versions, security patches, or device-specific variants. Jailbreak tools check builds, not version strings. IPSW files are tied to builds. Signing status is tracked per build.

Find your build number

Go to Settings → General → About. The Software Version row shows your version with the build in parentheses, e.g. 18.2 (22C160).

Major version map

Every major prefix and what OS it corresponds to:

23
iOS 19 / macOS 16
22
iOS 18 / macOS 15 Sequoia
21
iOS 17 / macOS 14 Sonoma
20
iOS 16 / macOS 13 Ventura
19
iOS 15 / macOS 12 Monterey
18
iOS 14 / macOS 11 Big Sur
17
iOS 13 / macOS 10.15
16
iOS 12 / macOS 10.14
15
iOS 11 / macOS 10.13
14
iOS 10 / macOS 10.12