How to Back Up Your Phone Before Selling It (iPhone & Android)

The most expensive mistake people make when selling a phone isn’t the price — it’s what they lose after the reset. Chat history that never reached the cloud, an authenticator app that was the only way into a bank account, photos that were “definitely syncing” but weren’t. Once you erase the phone and hand it over, there is no undo.

This guide shows you how to make a backup you can actually trust: what each backup method saves, the apps that need their own export, how to prove the backup worked before you erase, and the order of steps that keeps your accounts safe while the buyer gets a clean phone.

Why “it syncs to the cloud” is not a backup plan

Syncing and backing up are different things. Sync keeps one live copy across devices — delete something on one device and it disappears everywhere. A backup is a snapshot you can restore later. Most phones use a mix of both, and the gaps between them are where data gets lost:

• Photos may be set to sync only on Wi-Fi, or paused because cloud storage is full.
• Many messaging apps keep their own backup, separate from the phone’s.
• Authenticator codes, banking app device bindings and some game progress are not included in phone backups at all, or are deliberately excluded for security.

So the plan is: one full device backup, plus individual exports for the apps that need them, plus a check that everything is really there.

Back up an iPhone

iCloud backup

Go to Settings → [your name] → iCloud → iCloud Backup, turn it on and tap Back Up Now while on Wi-Fi and charging. When it finishes, the “Last successful backup” time updates. An iCloud backup includes device settings, app data, home screen layout, messages (unless Messages in iCloud is on, in which case they sync separately) and photos only if iCloud Photos is off. Apple lists exactly what is included on its iCloud backup support page.

Computer backup

Connect to a Mac (Finder) or a Windows PC (Apple Devices app or iTunes), select the iPhone and choose Back up all of the data on your iPhone to this computer. Tick Encrypt local backup — only encrypted backups include saved passwords, Health data and Wi-Fi settings. Write the encryption password down; without it the backup cannot be restored.

Photos

If iCloud Photos is on, open Settings → [your name] → iCloud → Photos and confirm it isn’t paused. Then look at photos.icloud.com on a computer and make sure your most recent pictures are there. If you don’t use iCloud Photos, import them to a computer.

Back up an Android phone

Open Settings → Google → Backup (on some phones Settings → System → Backup) and tap Back up now. Google’s backup covers app data for apps that support it, call history, contacts, device settings and SMS messages. Photos and videos are handled by Google Photos — open the app, tap your profile picture and confirm Backup complete.

Samsung users can also use Settings → Accounts and backup → Samsung Cloud or Smart Switch, which copies almost everything — including app layouts and many app files — to a computer, an external drive or directly to a new Galaxy phone. Smart Switch is the most complete option if your next phone is also a Samsung.

The apps that need their own backup

WhatsApp and other chats

WhatsApp keeps its own backup: Settings → Chats → Chat backup → Back up. On iPhone it goes to iCloud; on Android it goes to Google Drive. Moving between iPhone and Android uses WhatsApp’s own transfer process, not the cloud backup — do it while you still have both phones. Telegram stores chats in the cloud already; Signal requires its own transfer or backup, so follow the app’s instructions before you erase.

Two-factor authenticator apps

This is the one that locks people out of accounts. Google Authenticator can sync codes to your Google account or export them with a QR code from Transfer accounts. Microsoft Authenticator and others have their own cloud backup. If an app has no backup, sign in to each service and move 2FA to the new device, or save the recovery codes. Read our guide to securing your Apple ID and Google account before you start.

Banking, eSIM and game progress

Banking apps are usually tied to the device and must be registered again on the new phone — make sure you can log in without the old one. If you use an eSIM, transfer it or ask your carrier for a new QR code before you erase; our eSIM transfer guide explains the options. Games often save to a game account rather than the phone, so link them first.

Verify the backup before you erase

A backup you haven’t checked is a hope. Spend five minutes on these:

1. Check the date and time of the last successful backup in iCloud or Google settings.
2. Open your photos library on a computer or the web and spot-check the latest photos and videos.
3. Open WhatsApp’s chat backup screen and confirm the date and size look right.
4. Sign in to your 2FA-protected accounts from another device to prove you can still get in.
5. If you have the new phone, restore to it now and use it for a day before you erase the old one.

Then sign out, erase and prove the phone is clean

Only when the backup is confirmed should you sign out and reset. On iPhone, turn off Find My and sign out of your Apple ID first, then erase. On Android, remove your Google account before the reset so the buyer won’t hit Factory Reset Protection. Our turn off Find My before selling and factory reset guide walk through both.

Finally, give the buyer proof. Run an All-in-one Basic Info check or a model description and Find My check after the reset to show that Find My is off, and a GSMA blacklist check to show the IMEI is clean. If the phone was ever managed by an employer, an MDM status check confirms it isn’t enrolled. A clean report usually helps you sell faster and at a better price — see our guide to selling a phone safely.