How do I see what's taking up storage on my iPhone?

Open Settings > General > iPhone Storage. After a short load you'll see a color-coded bar of every category (photos, apps, media, system data) plus a ranked list of your apps by size, each with recommendations.

Why can't I tell which photos are using the most space in Settings?

Settings only shows the total for Photos, not per-photo sizes. To find the heavy individual files, sort your library by size with a cleaner app like Odoa, which surfaces the biggest videos first, or export and check file sizes manually.

What is System Data on iPhone and why is it so big?

System Data bundles caches, logs and temporary files iOS manages itself. A few gigabytes are normal; tens of gigabytes usually mean caches that a restart (or worst case, backup-and-restore) will shrink.

How much free space should my iPhone have?

Aim to keep at least 10% free. iOS needs headroom for updates, caching and camera recording; running at 99% full causes crashes, failed photos and sluggishness.

How to Check What's Taking Up Space on Your iPhone

Before deleting anything, it pays to see the actual breakdown. Guessing wastes effort on the wrong fixes; the iPhone Storage screen tells you precisely where your gigabytes went and even suggests quick wins. Here’s how to read it like a pro.

The main screen: your storage map

Open Settings.
Tap General > iPhone Storage.
Wait a few seconds while iOS calculates.

You get two things:

The colored bar: Photos, Media, Apps and System Data as proportional slices.
A ranked app list: largest apps first, each showing its app size plus its documents and data.

Tap any app for its detail page, including options like Offload App (remove the app, keep its data).

Read the categories the right way

Photos dominating? Expected on most phones, and the most fixable category. Start with why photos take up so much space.
A single app ballooning? Open its page. Social apps hoard caches; Messages grows from years of attachments (how to trim it).
System Data huge? A restart shrinks some of it. If it stays absurd, backup-and-restore rebuilds it.
Media large but Photos small? That’s downloaded music and podcasts; offloading rarely-played albums is painless.

Use Apple’s own recommendations

Above the app list, iOS suggests actions tailored to your usage: reviewing large attachments, offloading unused apps, enabling iCloud Photos. These are worth a look, though they all push toward cloud storage; if you’d rather keep everything local, cleanup beats migration. See freeing space without deleting for both routes.

Drill into the photo problem

Settings lumps all photos together, which hides the real story. The usual suspects behind a fat Photos slice:

Large videos, where a handful outweigh thousands of stills
Burst frames hidden under single thumbnails
Live Photos costing double
Screenshots accumulated over years

Swipe-based cleaners expose these directly: Odoa sorts your library by actual file size, groups duplicates, and filters screenshots, all on-device. That turns the vague “Photos: 84GB” bar into an actionable list. For the method, see cleaning up your camera roll.

Keep 10% free, always

Whatever your capacity, treat the last 10% as reserved for iOS: updates fail, photos refuse to save, and performance sags when you’re pinned at full. If you’re bumping that line monthly, work through the real fix for storage-full warnings.

The bottom line

Settings > General > iPhone Storage shows exactly where your space goes and ranks your biggest offenders. Fix the top category first, usually photos, by clearing the dead weight rather than migrating it, and keep a tenth of your storage empty so iOS can breathe.