How to Find and Register an iPhone UDID for Ad-Hoc Distribution (2026)

Q: How do I find my UDID without a computer?

Open a service that reads the identifier from an installed configuration profile, or use a distribution tool's registration link that captures the UDID when the tester opens it on the device. Both work without a Mac; the tester just taps a link on the iPhone.

Q: How long does UDID registration take?

The first devices you add usually register immediately, while larger batches can take longer to propagate — plan for up to 24 to 72 hours before a newly added device works. After registering, rebuild the app with an updated provisioning profile.

Q: Can I add a device without rebuilding the app?

No. An ad hoc build only runs on the UDIDs baked into its provisioning profile at build time, so adding a device means regenerating the profile and rebuilding. Tools that automate ad hoc rebuild and re-sign for you when a new device registers.

Jan Thalheim

Aug 27, 2026 • 7 min read

To install an ad hoc iOS build, you need each device's UDID — a unique 40-character (or newer 25-character with a dash) identifier — registered in the Apple Developer portal and included in the provisioning profile before you build. You can find a UDID manually via Finder or a configuration profile, or collect it automatically from testers' devices with a distribution tool. This guide covers both, plus the registration limits that catch teams out.

Ad hoc distribution has no store review and no 90-day expiry, but this UDID step is its price of admission. Automating it is the difference between smooth testing and chasing testers for a string of characters.

Finding a UDID

Via Finder (macOS):

Connect the iPhone to a Mac and open Finder.
Select the device in the sidebar.
Click the info line under the device name (model/storage) until it cycles to show the UDID.
Right-click → Copy UDID.

Via Settings / a web profile: Testers without a Mac can install a small configuration profile from a UDID-reading web service, which displays and sends you the identifier — no computer required.

For testers without a Mac: the practical answer is a registration link (see automatic collection below) — don't ask non-technical testers to read a 40-character ID out loud.

Registering a UDID in the Apple Developer portal

Sign in to the Apple Developer portal → Certificates, Identifiers & Profiles → Devices.
Click +, choose the platform, and paste the UDID with a name.
Processing time: the first devices typically register immediately; larger batches can take up to 24–72 hours to propagate.
Rebuild the provisioning profile to include the new device, then rebuild and re-sign the app. (See provisioning profiles and code signing.)

Collecting UDIDs at scale — the manual pain vs automation

Registering one or two devices by hand is fine. Onboarding a whole client team is where ad hoc hurts: every new device means a UDID request, a portal entry, a profile rebuild and a fresh build.

Distribution tools remove this. With Appisto, the tester opens an install link and the device registers its own UDID automatically — you don't ask, they don't read out characters, and the build is made available to them without the manual round-trip. It's the single biggest friction remover in ad hoc distribution, and it works the same for sending builds to clients.

The limits to know

100 devices per product type per membership year (100 iPhones + 100 iPads count separately).
Disabling a device does not free a slot — the count only resets once a year at renewal.
Plan device hygiene around that annual reset (see the 100-device limit guide).

Frequently asked questions

How do I find my UDID without a computer? Install a UDID-reading configuration profile, or open a distribution tool's registration link on the device — both capture it without a Mac.

How long does UDID registration take? The first devices register immediately; larger batches can take up to 24–72 hours. Then rebuild the profile and app.

Can I add a device without rebuilding the app? No — ad hoc builds only run on UDIDs baked in at build time. Tools that automate ad hoc rebuild and re-sign for you.

Key takeaways

Ad hoc needs each device's UDID registered and baked into the profile before building.
Find it via Finder or a config profile; register it in the Apple Developer portal.
You're capped at 100 devices per product type per year, and disabling doesn't free a slot.
Appisto collects UDIDs automatically when testers open the link — the main ad hoc chore, gone. See TestFlight vs ad hoc and the iOS distribution matrix.