How Long Should iPhone 18 Quick Start Take? (and Why It Sometimes Takes 16 Hours)

There is no single supported number of hours that Quick Start should take. A long estimate can reflect the amount of data being moved and the connection being used. The reliable completion signal is the loading bar on the new iPhone, not a predicted duration on the old phone.

Keep both devices near each other, connected to power, and on Wi-Fi while the transfer is active. Apple notes that the whole transfer can take a while depending on how much content is moving.

Check that the transfer can continue

• Keep the old and new iPhones plugged in.
• Keep Wi-Fi and Bluetooth available for the setup process.
• Do not use either phone for other tasks until the new iPhone loading bar finishes.
• Confirm the new iPhone has enough available storage for the content being transferred.

When to treat it as a stalled transfer

A large time estimate by itself is not proof that the process has failed. Instead, watch for a loading bar that stops making progress for an extended period, a disconnect, or an error message. If setup no longer continues, restart both devices and begin the transfer again.

If the new iPhone was already set up and you need to repeat the transfer from the setup flow, it must be erased first so that the Hello screen returns. If storage was insufficient or only some content transferred, make space on the new iPhone before retrying. After the iPhone-side loading bar finishes, complete setup and then verify important apps and data.