Where to find it
On iPhone and iPad: Settings → General → About. The version is listed at the top; tap the version number itself and it expands to reveal the build. On a Mac: the Apple menu → About This Mac, then click the version number to reveal the build.
On an Apple Watch it is in the Watch app on your iPhone under General → About, and on an Apple TV under Settings → General → About. Every Apple platform exposes it, and every one of them hides it one tap deeper than the version.
How to read it
A build number looks like 23A344 or 24A5308f. The leading number is the internal major version, the letter marks the development milestone, and the digits identify the specific build. What matters for our purposes is the pattern that follows the letter.
Shipping builds carry a short numeric suffix — 23A344. Beta builds carry a longer one beginning with a 5, usually with a trailing letter — 24A5308f. If your suffix starts with a 5 and ends in a letter, you are on a beta. That rule has held across Apple's platforms for years and is the fastest check there is.
Why it matters
Two devices can report the same version number while running different builds — for example a release candidate and the public release that followed it. If you are troubleshooting, or comparing notes with someone else, the build number is the only thing that identifies your software precisely.
It also settles the most common question people have after leaving a beta: am I actually on the shipping release now? The version number will not tell you if the numbers happen to match. The build number always will.
Checking whether you are still on a beta
Beyond the build number, Settings → General → Software Update → Beta Updates shows which channel, if any, your device is subscribed to. Bear in mind that turning the channel off does not change the build you are currently running — it only stops new ones arriving.
So the two checks answer different questions. Beta Updates tells you what you will receive next; the build number tells you what you are on right now. Our exit guide explains why that distinction catches people out.
Including it in a bug report
Feedback Assistant captures the build automatically, which is one reason reports filed through it are far more useful than an email or a forum post. If you are describing a problem anywhere else, quote the build rather than the version.
Our bug reporting guide covers what else makes a report actionable — reproduction steps and a sysdiagnose captured while the problem is fresh.
Frequently Asked Questions
Where do I find my iPhone's build number?
Settings → General → About, then tap the version number — it expands to show the build.
How can I tell if a build number is a beta?
Beta builds have a longer suffix beginning with 5 and usually ending in a letter, such as 24A5308f. Shipping builds have a short numeric suffix such as 23A344.
Why do two devices show the same version but behave differently?
They are probably on different builds of that version — for example a release candidate and the public release. The build number is what distinguishes them.
Does turning off Beta Updates change my build number?
No. It stops new betas arriving but leaves you on the build you already have until a newer release supersedes it.