A factory reset erases everything on your phone and returns it to the state it arrived in
When you reset your phone, the operating system wipes your storage clean — all photos, messages, apps, contacts, and files disappear. The phone then reinstalls its original software and settings, as if you just unboxed it. This is different from restarting, which simply turns the phone off and back on without erasing anything.
There are two types of resets. A soft reset (or restart) closes all apps and clears temporary memory, but keeps your data intact. A factory reset (or hard reset) removes everything. Most people mean factory reset when they say "reset my phone," and that is what this guide covers.
On Android, you find the factory reset option in Settings > System > Reset options > Erase all data. On iPhone, it is Settings > General > Transfer or Reset > Erase All Content and Settings. Both will ask you to confirm before proceeding, because the action cannot be undone.
Key Takeaways
- A factory reset deletes all photos, messages, apps, contacts, and personal files stored on your phone's internal storage.
- Data backed up to cloud services like Google Drive, iCloud, or OneDrive remains safe and can be restored after the reset.
- Apps you downloaded from the app store can be reinstalled, but you will need to sign back into each one with your account credentials.
- A factory reset does not remove your phone number or carrier account — it only clears the device itself.
- You should back up your data before resetting, because once the reset completes, local data cannot be recovered.
What data actually gets deleted
A factory reset removes data stored directly on your phone's internal storage. This includes photos and videos in your camera roll (unless they are also in Google Photos or iCloud), text messages, call history, contacts saved to the phone rather than your Google or Apple account, notes, calendar events, browser history, and any files in your Downloads or Documents folders.
Downloaded apps are also removed, though the app store remembers which ones you installed. After the reset, you can reinstall them by signing into your app store account (Google Play on Android, App Store on iPhone) and downloading them again. Your login credentials for those apps are not stored on the phone itself, so you will need to enter them again.
Anything backed up to the cloud — Google Drive, Google Photos, iCloud, OneDrive, Dropbox, or similar services — stays in your cloud account and is not affected by the reset. This is why backing up before you reset is so important.
What data stays on your phone after a reset
Your phone number and carrier account remain unchanged. The reset only affects the device's storage and software, not your relationship with your mobile carrier. Your SIM card (if your phone uses one) is not erased.
If you signed into your Google account or Apple ID before the reset, the phone may ask you to sign in again after it restarts. Once you do, it can automatically restore some data — your contacts, calendar, email, and app settings — from your account's cloud backup. This is called account recovery, and it happens automatically if you choose to restore during setup.
Any data stored in third-party cloud services (like Gmail, Outlook, Slack, or banking apps) is also unaffected, because it lives on those companies' servers, not on your phone. You simply sign back into those apps after the reset to access it again.
Why people reset their phones
The most common reason is to prepare a phone for sale or donation. A factory reset ensures the new owner does not inherit your personal data, messages, or login credentials. Before selling or giving away a phone, always reset it.
People also reset phones to fix persistent software problems — apps crashing repeatedly, the phone running slowly, or the battery draining unusually fast. A reset clears out corrupted files and temporary data that might be causing the issue. It is often the last troubleshooting step before contacting the manufacturer or carrier.
Some people reset to remove malware or spyware, though this is less common on modern phones. If you believe your phone is infected, a factory reset will remove it, but only if you then avoid reinstalling the app or visiting the site that caused the infection in the first place.
How to back up before you reset
On Android, open Settings > Google > Manage your Google Account > Backup. Make sure "Backup to Google One" is turned on. This backs up your contacts, calendar, SMS messages, app data, and device settings to your Google account. Photos and videos require a separate backup to Google Photos, which you can enable in the Photos app settings.
On iPhone, go to Settings > [Your Name] > iCloud and turn on iCloud Backup. This backs up your photos, messages, contacts, calendar, notes, and app data to your iCloud account. You can also manually back up to a computer by connecting your iPhone and opening Finder (on Mac) or iTunes (on Windows), then clicking Back Up Now.
Before you reset, also check whether important apps like banking, email, or messaging have their own backup or export options. Some apps let you download your data directly. It takes a few minutes but gives you an extra layer of protection.
What happens during and after the reset
The reset process takes 5 to 15 minutes, depending on how much data is on your phone. Do not turn off the phone or remove the battery during this time. The phone will restart several times and show a progress bar. Let it finish completely.
Once the reset is done, the phone boots up as if it is brand new. You will see the initial setup screen, where you choose your language and connect to Wi-Fi. At this point, you can sign into your Google or Apple account to restore your backed-up data, or you can set up the phone as a new device.
If you are selling or donating the phone, do not sign back into your account. Instead, leave it at the setup screen or complete setup without signing in. This ensures the new owner can set up their own account without your data in the way.
Recovering data after a reset
If you reset your phone without backing up first, recovery depends on what data you are trying to recover. Cloud-based data — email, contacts synced to Google or iCloud, photos in Google Photos — is still in your cloud account and can be accessed by signing in on any device or computer.
Local data that was not backed up — photos only on your phone, text messages, notes — cannot be recovered after a factory reset. The data is overwritten when the phone reinstalls its software. There are data recovery services that claim to retrieve deleted files, but they are expensive and do not always work on modern phones with encrypted storage.
The best approach is to prevent this situation by backing up regularly. Set up automatic cloud backup on your phone so that your data is protected even if you reset unexpectedly.
Frequently Asked Questions
Will a factory reset remove viruses or malware from my phone?
Yes, a factory reset removes malware because it deletes all files and reinstalls the original operating system. However, if the malware came from an app you downloaded, you will reinfect your phone by reinstalling that app. After resetting, only reinstall apps from the official app store and avoid the source of the infection.
Can I undo a factory reset?
No, a factory reset cannot be undone. Once it completes, any data not backed up to the cloud is gone permanently. This is why backing up before you reset is so important. If you change your mind before the reset finishes, turn off the phone immediately — some phones allow you to stop the process if you act quickly enough.
Do I need to reset my phone before selling it?
Yes, always reset your phone before selling or giving it away. A factory reset removes your personal data, messages, photos, and login credentials so the new owner cannot access them. After the reset, do not sign into your account — leave the phone at the setup screen so the buyer can set it up with their own account.
Will I lose my phone number if I reset?
No, your phone number stays with your carrier account, not your phone. A factory reset only affects the device's storage and software. Your carrier will continue to recognize your phone number on the same SIM card or account.
How long does a factory reset take?
Most factory resets take 5 to 15 minutes from start to finish. The phone will restart multiple times during the process. Do not interrupt it by turning off the phone or removing the battery, or the reset may fail and leave your phone in an unusable state.