The fastest way to reduce your iPhone backup size before switching phones is to clean the phone first — trim large videos, remove duplicate photos, and clear app downloads — because the backup mirrors what is on the device. Then exclude bulky apps you do not need to carry over in Settings > [your name] > iCloud > Manage Account Storage > Backups. A smaller, cleaner backup transfers faster and restores cleanly onto the new phone.
TL;DR
- Your backup mirrors the phone — clean the device first and the backup shrinks with it.
- Trim large videos and duplicate photos before backing up (the biggest savings).
- Exclude heavy apps from the backup: iCloud > Manage Account Storage > Backups > [device].
- A leaner backup restores faster and avoids carrying junk to the new phone.
- Do a fresh backup after cleaning, not before.
Why is my iPhone backup so big?
The backup includes your Photos library (if not already in iCloud Photos), app data and downloads, messages and their attachments, and settings. So it is roughly as big as the used space on your phone. A cluttered phone makes a cluttered backup — and a slow, error-prone transfer to the new device.
The right order: clean, then back up
- Trim large videos — the single biggest backup component. (See how to find and delete large videos.)
- Remove duplicate and similar photos — you do not want to carry five copies of one moment to the new phone.
- Clear app downloads — streaming, podcasts, and game data re-download on the new device anyway.
- Empty Recently Deleted — Photos > Albums > Recently Deleted > Delete All.
- Then back up — Settings > [your name] > iCloud > iCloud Backup > Back Up Now, or back up to a computer.
Exclude bulky apps from the backup
If a few apps hold large data you do not need to carry over:
- Settings > [your name] > iCloud > Manage Account Storage > Backups.
- Tap your device.
- Toggle off large apps you do not need backed up (their data re-creates or re-downloads on the new phone).
What iOS does natively, and where it stops
iOS lets you exclude apps from a backup and shows each app's backup size — use that to drop obvious bulk. Where it stops: it will not trim your Photos library, which is usually the largest part of the backup. Removing duplicates and big videos is manual, and it is exactly what makes the backup (and the transfer) dramatically smaller.
Clean once, transfer light
Cleanor for iPhone finds large videos, duplicates, and similar photos on-device, so you can slim the phone — and therefore the backup — in one pass before you switch. Nothing is uploaded. For the full routine, see the free up iPhone space guide.
What this cannot do
Excluding an app from the backup means its local data will not transfer, so only exclude apps whose data is disposable or cloud-synced. And a backup made before cleaning will still be large — always clean first, then create a fresh backup.
FAQ
How do I make my iPhone backup smaller?
Clean the phone first — trim large videos, remove duplicate photos, clear app downloads — then exclude bulky apps in iCloud > Manage Account Storage > Backups and create a fresh backup.
Why is my iPhone backup so large?
The backup mirrors your device: Photos, app data and downloads, messages with attachments, and settings. A full phone makes a full backup.
Will excluding apps from backup lose data?
Only that app's local data, which often re-downloads or re-creates on the new phone. Exclude only apps whose data is disposable or synced to the cloud.
Should I clean before or after backing up?
Before. A backup made before cleaning is still large. Clean the phone, then run a fresh backup so the transfer is fast and clean.
Next: iPhone Photos using 80GB? How to cut it safely and iPhone storage full but nothing to delete. To slim the phone and the backup in one pass, get Cleanor for iPhone.