You open Settings → General → iPhone Storage, tap an app, and see two numbers: App Size and Documents & Data. The second one is often huge. WhatsApp, Telegram, Spotify, Safari, and a dozen other apps can sit on several gigabytes with no obvious “Clear” button on that screen.
That line is not Photos. It is not the app you downloaded from the App Store. It is the app’s sandbox. This guide shows how to read it, what iOS will and will not let you delete from Settings, and the safe in-app ways to shrink it without wiping the app itself. Button names can vary by iOS version — if yours says Storage instead of iPhone Storage, follow the same path.
What Documents & Data Actually Is
Every iOS app gets a private folder. Apple labels that folder Documents & Data. Typical contents:
- Caches — thumbnails, temporary downloads, web views. Sometimes iOS reclaims these; often it does not until you clean inside the app.
- Offline files — Spotify / Apple Music downloads, maps, files you opened once.
- Databases — chat history, search indexes, local settings.
- Downloaded media — WhatsApp videos, Telegram files, Safari PDFs that live in the app or in Files.
It is not your Camera Roll (that is Photos). It is not the app binary (that is App Size). Mixing those three is why people offload WhatsApp and wonder why storage barely moved. For the system-wide leftover bar, see what System Data is on iPhone — a different bucket.
Quick check: Settings → General → iPhone Storage → tap the app. If Documents & Data is larger than App Size, the sandbox is the problem, not the download. Clean inside the app first.
How to See App Size vs Documents & Data
- Open Settings → General → iPhone Storage (some iOS builds label this Storage).
- Wait for the list to finish calculating. The top apps are usually the ones that matter.
- Tap an app. Read the two lines: App Size (the binary) and Documents & Data (the sandbox).
- Note the Documents & Data number before you change anything so you know what you freed.
Sort mentally: Photos is its own row. Music, Podcasts, Safari, WhatsApp, and Telegram each have their own Documents & Data. What’s taking up space walks the bars in order if you want the full map.
What You Can (and Cannot) Delete on That Screen
On most apps, iPhone Storage offers Offload App and Delete App. It does not offer a universal Clear Documents & Data button. A few Apple apps expose extra actions (Music downloads, Safari data in Settings → Safari). Third-party apps almost never do.
- You cannot tap Documents & Data to empty it. That number is informational.
- Offload leaves Documents & Data in place. The icon stays, with a cloud badge, until you tap it again.
- Delete App removes the binary and the sandbox. Local chats, downloads, and caches that were not in iCloud are gone.
So if you want to keep the app and still shrink the number, you work inside the app — or you delete and reinstall knowing you will lose unsynced local data.
Safe Ways to Shrink Documents & Data (Per App Type)
WhatsApp and Telegram
Chat apps store media in the sandbox even when you also saved a copy to Photos. That is why WhatsApp can look huge twice. Open WhatsApp → Settings → Storage and Data → Manage Storage (wording varies). Review large chats, delete unused media in-app, and turn off auto-download of videos on cellular. Telegram has a similar Data and Storage / Storage Usage screen. Step-by-step for WhatsApp: how to delete WhatsApp media on iPhone.
Spotify, Apple Music, and other streaming apps
Offline playlists live in Documents & Data, not in Photos. In Spotify, remove Downloads / Offline playlists and turn off auto-download. In Apple Music, use Remove Download / Remove All Downloads so the library stays and only the offline copy goes. Full Music walkthrough: how to delete Apple Music downloads.
Safari and Files
Safari downloads land in the Files app (On My iPhone → Downloads), not in Photos. Delete PDFs, ZIPs, and videos there, then empty Recently Deleted in Files or the space still counts. Safari caches and history are Settings → Safari → Clear History and Website Data (that also signs you out of sites). See how to delete Safari downloads and how to clear cache on iPhone.
Offload vs delete vs delete-and-reinstall
Offload Unused Apps (Settings → General → iPhone Storage → Offload Unused Apps, or Offload App on one app) removes App Size only. Documents & Data stays. Use it when the binary is large and you rarely open the app. Full comparison: offload unused apps vs delete.
Delete-and-reinstall is the nuclear in-app reset: Delete App, then download it again. The sandbox starts empty. Warn: anything not in iCloud or the app’s cloud backup is gone — local chats, offline files, unsynced drafts. Confirm a backup first. Then reinstall from the App Store.
Offload Unused Apps
Removes the app binary. Keeps Documents & Data. Icon stays. Reinstalling the binary restores your local files. Does not shrink a fat sandbox.
Delete App
Removes the binary and the sandbox. Frees both numbers. Local data not in iCloud is gone. Use only when you accept that loss or already cleaned in-app.
In-app cleanup
Best first move. Manage Storage, Remove Downloads, delete Files, clear Safari data. You keep the app and most of your account. Documents & Data drops without a reinstall.
Delete and reinstall
Wipes the sandbox, then you download a fresh binary. Last resort after in-app tools. Will lose chats and files that never left the phone. Offload is safer if you only need App Size gone.
What Will Not Shrink Documents & Data
These are real storage wins elsewhere. They do not touch an app’s sandbox:
- Emptying Photos Recently Deleted. That only frees photos and videos still counting in Photos. It will not drop WhatsApp or Spotify. See how to empty Recently Deleted when Photos is the bar that will not move.
- Compressing videos in Photos. Smaller Camera Roll files. Documents & Data for other apps stays the same.
- Restarting the phone. May trim a little cache. Will not delete chat media or offline music.
- Offloading the app when Documents & Data is the large number. You already know why.
If the phone is full and you want to keep memories, pair sandbox cleanup with freeing storage without deleting keepers — offload, compress, caches — instead of wiping the camera roll first.
Where Cleanup My Phone: AI Cleaner Helps
Cleanup My Phone: AI Cleaner (App Store id 6748653777 — not Cleanup by Codeway, not CleanMyPhone by MacPaw) does not clear per-app Documents & Data. iOS does not let third-party apps empty another app’s sandbox. WhatsApp media, Spotify downloads, and Safari files stay in Settings and those apps.
Where it helps after you shrink Documents & Data is the Photos side of a full phone: duplicates, similar shots, screenshots, and oversized videos, all scanned on-device. Photos never leave the phone. Deletions go to a 30-day undo vault.
- On-device Photos cleanup — duplicates, similar, screenshots, large videos.
- 30-day undo vault on everything the app deletes.
- Does not wipe Documents & Data / Music / system files — those stay in Settings and the apps that own them.
Start at cleanupmyphone.com when Photos is the next bar after the sandbox.
Clean Photos After You Shrink Documents & Data
Cleanup My Phone: AI Cleaner finds duplicates, similar shots, screenshots, and oversized videos on your iPhone. On-device only. 30-day undo vault. It does not clear per-app Documents & Data.
Download Free →Frequently Asked Questions
Does Offload Unused Apps clear Documents & Data?
No. Offload keeps Documents & Data so your files return when you tap the icon. If that number is the large one, clean inside the app or delete the app (and accept local data loss).
Does restarting the iPhone help?
A restart can drop a little temporary cache. It will not wipe WhatsApp videos, Spotify downloads, or Safari files. Clean in-app first; reboot after if the storage list looks stale.
Will reinstalling lose my chats?
It can. Delete App wipes the sandbox. Chats and files that never synced to iCloud or the app’s cloud are gone. Confirm a backup before you delete. Offload does not delete chats.
Can Cleanup My Phone: AI Cleaner wipe Documents & Data?
No. Cleanup My Phone: AI Cleaner cleans Photos on-device (duplicates, similar shots, screenshots, large videos) with a 30-day undo vault. It cannot empty another app’s sandbox. App Store: apps.apple.com/app/id6748653777. Not Cleanup by Codeway. Not CleanMyPhone by MacPaw.