The iCloud date
Settings → your name → iCloud → iCloud Backup. The date and time of the last successful backup appear at the bottom of the screen, below the Back Up Now button.
That word — successful — is the important one. A backup that starts every night and fails every night shows an old date here and no error anywhere else. This screen is the only honest signal iOS gives you.
What an old date usually means
Full iCloud storage, by a wide margin. The free 5 GB tier is not enough for a modern iPhone, and when it fills, backups simply stop completing. Settings → your name → iCloud → Manage Account Storage shows whether that is the case.
After storage, the usual causes are a Wi-Fi network that drops the connection overnight, a phone that is not being charged at night, or Back Up This iPhone having been switched off at some point and forgotten. Our iCloud storage guide covers the first.
The computer date
On a Mac, connect the iPhone, select it in Finder and look at the General tab: the last backup date to that computer is listed there, and Manage Backups shows every backup with its date and size. On Windows the Apple Devices app shows the same.
Remember these are separate records. A phone can have a recent iCloud backup and a computer backup from two years ago, or the reverse.
Check before anything significant
Before an iOS update, before a repair, before travelling, before selling. Five seconds on the iCloud Backup screen, and if the date is old, tap Back Up Now and wait.
This is the whole discipline. Most people who lose data had backups configured — they just had not run in months and nobody looked.
Force one now
Tap Back Up Now on the iCloud Backup screen. The phone needs Wi-Fi and, for a first backup or one after a long gap, patience — it can take a long time. Keep the screen open and the phone on power.
If it stalls at the same point repeatedly, storage is the likely cause. A computer backup costs nothing regardless of size and is more complete — our computer backup guide covers it.
Frequently Asked Questions
Where do I see my last iPhone backup date?
Settings → your name → iCloud → iCloud Backup. The last successful backup date is at the bottom of that screen.
Why has my iPhone not backed up in weeks?
Almost always full iCloud storage. Backups stop completing silently when the allowance runs out.
Does iOS warn me when backups fail?
Not reliably. The last-backup date is the only dependable signal, which is why checking it periodically matters.
How do I force a backup right now?
Tap Back Up Now on the iCloud Backup screen, on Wi-Fi and connected to power.