Apple Firmware Build Database

Build Number Decoder Engine

Decode any Apple firmware build string instantly. Understand the version, platform, signing status, and compatible devices – all from live data.

LiveBuild Data
AllApple Platforms
DecodeAny Build String
0Decodes Today
Build Anatomy

Decode any Apple build
number in seconds.

01
Enter Build String

Type any Apple firmware build number e.g. 22C160, 21A326, or 23D8133 into the decoder.

02
Instant Decode

See the iOS version, platform, release date, and live signing status at a glance.

03
View Devices

See which devices support this build with direct links to firmware downloads.

04
Download IPSW

Get direct Apple CDN download links and cryptographic checksums for verification.

Build Number Decoder

Decode your firmware build.

build_decoder — live apple firmware database

Build numbers follow the pattern: 22C160 = iOS 18.2 (22 = iOS 18, C = .2, 160 = build revision).

Try: 22C160  ·  21A326  ·  23D8133  ·  20H115

Querying build database…

Could not decode build number. Check the format and try again.

Build Structure
Deep Dive

Understanding Apple's
build number system.

build_anatomy.sh
$ decode build 22C160 Analyzing build string... ✓ Major: 22 = iOS 18 / macOS 15 ✓ Minor: C = .2 (third major release) ✓ Patch: 1 = first build revision ✓ Build: 60 = specific build variant
$ decode build 21A326 Analyzing build string... ✓ Major: 21 = iOS 17 / macOS 14 ✓ Minor: A = .0 (first release) ✓ Build: 326 = specific build variant
$
Build Number Structure

Apple build numbers follow a consistent pattern: Major + Minor + Patch + Variant. The Major (first two digits) indicates the OS generation. The Minor letter maps to the version number (A = .0, B = .1, C = .2). The Patch number increments for new builds, and the Variant suffix identifies device-specific versions.

Major Version Mapping
23 = iOS 19 / macOS 16 22 = iOS 18 / macOS 15 21 = iOS 17 / macOS 14 20 = iOS 16 / macOS 13 19 = iOS 15 / macOS 12 18 = iOS 14 / macOS 11 17 = iOS 13 / macOS 10.15 16 = iOS 12 / macOS 10.14
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, and signing status is tracked per build. The build number is the definitive identifier for firmware.

Check signing status Verify IPSW integrity Jailbreak compatibility Device-specific variants
FAQ

Frequently asked questions.

Everything you need to know about Apple build numbers and how to use this decoder.

A build number is Apple's internal identifier for a specific firmware version. Unlike the public version number (e.g., iOS 18.2), build numbers uniquely identify every build, including developer betas, security updates, and device-specific variants. For example, 22C160 is the build number for iOS 18.2 on most devices.
Go to Settings → General → About. Look at the "Software Version" row. The build number appears in parentheses after the version number, e.g., 18.2 (22C160). On Mac, click the Apple logo → About This Mac → the build number is shown below the macOS version.
The letter indicates the minor version: A = .0 (first release), B = .1, C = .2, D = .3, and so on. For example, build 22C160 has "C" meaning it's the third major release (iOS 18.2). Build 21A326 has "A" meaning it's the first release (iOS 17.0).
Yes, frequently. Different device families often receive different build numbers for the same public iOS version. This is especially common with older devices that may get a different build with device-specific fixes, or when Apple releases a version for newer devices but not older ones. The build number is the definitive way to identify exactly which firmware your device is running.
When you decode a build number, the signing status is shown directly in the results. A Signed badge means Apple's TSS servers will currently approve restores to this build. Unsigned means restores are no longer possible through official methods. This is crucial before attempting a restore or downgrade.