Every iPhone carries a unique identifier known as the UDID, a string of 40 characters that acts as its digital fingerprint. Finding this identifier is essential for tasks like enterprise app distribution, device registration with developers, or troubleshooting specific carrier issues. Unlike the IMEI or serial number, the UDID is the most precise reference for developers and advanced users who need direct access to a device.
What Exactly is a UDID?
The term UDID stands for Unique Device Identifier, and it is a cryptographic hash that distinguishes one iPhone from every other in the Apple ecosystem. This identifier was historically used for ad hoc app installations and development testing before Apple introduced more privacy-focused alternatives like DeviceCheck and App Attest. While Apple has restricted direct access to this value in recent iOS versions, it remains a crucial data point for enterprise workflows and technical support scenarios.
Retrieve the UDID via Finder (Mac or PC)
The most reliable method to view the UDID requires connecting the iPhone to a computer. This process bypasses the restrictions of the Settings app and retrieves the raw identifier string from the device itself. You will need a Mac running macOS Catalina or later, or a Windows PC with iTunes installed to follow these steps successfully.
Step-by-Step Connection Process
Use a certified USB cable to connect your iPhone to the computer.
Unlock the device and trust the computer if prompted.
Open Finder on macOS or iTunes on Windows.
Select your device icon once it appears in the sidebar or device menu.
Click on the "Summary" tab to view the basic information page.
Extracting the Identifier String
Once the device summary is visible, the UDID is presented in a formatted layout that is easy to copy. Apple displays this information in two distinct formats: a human-readable serial number format and the full hexadecimal string. For technical purposes, such as provisioning profiles, you must use the version that contains all 40 characters.
Viewing the Raw Data
To reveal the complete identifier, you need to interact with the serial number field on the summary page. By clicking on the serial number text itself, the interface dynamically switches to display the full UDID. This action copies the exact string to your clipboard, allowing you to paste it into emails, documents, or developer portals without manual transcription errors.
Alternative Methods and Limitations
While older tutorials might suggest taking screenshots of the Settings app, Apple removed the direct visibility of the UDID from the iOS interface years ago. Current versions of iOS obfuscate the full string behind a tap-to-reveal mechanism to prevent unauthorized tracking. Consequently, the device settings method is no longer a viable option for most users seeking the raw data.
Organizing Your Identifier Information
Given the importance of this identifier, maintaining a secure record is highly recommended. Copy the UDID and paste it into a secure note-taking application or a dedicated spreadsheet. Label the entry with the device name, model, and date of retrieval to ensure future reference is effortless. This practice saves time when managing multiple devices or submitting information to developers.
