Why is the Gmail app taking up so much space on my phone?

Last reviewed: October 7, 2026 · Markdown version

Because the app keeps a working copy of your mail on the phone: recent messages so they open offline, and on Android, attachments it downloads ahead of time. That copy lives in the phone's storage and is a different thing from the 15 GB in your Google Account. The account side, and what fills it, is on what takes up space in Gmail; this page is about the handset.

The two Android settings that decide the size

In the Gmail app, open Menu, Settings, then tap the account. Google's settings page lists what lives there, and two entries control most of the space (Change your Gmail settings (Android), read 7 October 2026):

Days of mail to sync. Google's description: "Choose the number of days of mail that you want to automatically sync and store on your device." A smaller number means less mail kept on the phone; the trade-off, per the same entry, is that mail outside the window is not available offline.
Download attachments. "When this setting is on, attachments are automatically downloaded if you're on Wi-Fi. If this setting is off, you can still download attachments manually." If your mail is heavy with PDFs and photos, this is the one to look at.

A third entry, Manage labels, lets you "Choose notification and sync settings for different labels". And note the scope line at the top of that section: when more than one account is in the app, the settings you change "only apply to the account you selected." Each account added to the app keeps its own copy, so check every account, not only the main one.

Clearing the app's cache on Android

Android shows per-app use under Settings, Storage. Android's help describes the two buttons you will find for an app (Free up storage on your Android device, read 7 October 2026):

"Clear cache: Deletes temporary data. Some apps may be slow the next time you open them."
"Clear storage: Permanently deletes all app data. Try to delete the data within the app first."

The same page notes that "Settings can vary by phone". For Gmail, clearing storage removes the phone's copy, not your mail, which stays in your Google Account; expect the app to download it again on the next sync, within whatever Days of mail to sync allows. That is why shrinking the sync window first, then clearing, is the order that actually saves space.

On iPhone

The iPhone Gmail app has fewer knobs. Google's settings page for it covers sender images, swipe actions, notifications, labels, signature, vacation responder, Smart Reply and search history; it lists no sync-days or attachment-download option (Change your Gmail settings (iPhone & iPad), read 7 October 2026). The controls you do have are Apple's.

Open Settings, General, then iPhone Storage, and tap Gmail. Apple's guide explains the two choices there (How to check the storage on your iPhone and iPad, read 7 October 2026):

Offload the app: "This frees up storage used by the app, but keeps its documents and data."
Delete the app: it "removes the app and its related data."

To shrink what Gmail's stored mail takes up on the phone, deleting and reinstalling is the step that applies, since offloading keeps the data; your mail is in your Google Account and comes back after you sign in again. Apple also warns that "Cached data and temporary data might not count as usage", so the figure on that screen may not be the whole story. Before you remove it, uninstalling and reinstalling Gmail covers what you will need to set up again.

One source of confusion on iPhone: Apple's storage list has a separate category, "Mail: Emails and their attachments." That is Apple's own Mail app. If you read Gmail there too, that copy is counted separately from the Gmail app.

Will deleting old emails shrink the app?

Less than you might hope. On Android, old mail outside the sync window is, by Google's description of that setting, not stored on the phone in the first place, so deleting it frees Google Account storage rather than phone storage. If the warning on screen says the phone is full, the steps above are the fix. If the warning says your Google storage is full, that is a different problem with a different page: phone storage or Google storage.