Why Is My iPhone So Slow? Fixes That Work

If your iPhone feels sluggish, the fastest fixes are freeing up storage, closing background apps, and restarting the device. For persistent slowness, updating iOS or resetting settings usually restores normal speed. Below are the most effective solutions, explained in order of what to try first.

Check Storage Space First

A nearly full iPhone is the most common cause of slowdowns. iOS needs free space for temporary files, app caches, and system updates. When storage drops below about 10–15%, the system starts struggling.

See what’s using space: Go to Settings > General > iPhone Storage. You’ll see a bar chart and a list of apps sorted by size.
Offload unused apps: Tap an app and choose Offload App – it deletes the app but keeps its documents and data, so you can reinstall later without losing progress.
Clear Safari cache: Settings > Safari > Clear History and Website Data (note: this signs you out of some sites).
Delete old messages: In Settings > Messages, set “Keep Messages� to 30 days or 1 year instead of Forever.
Remove large videos and photos: Use the Storage screen to see your largest files and delete or move them to iCloud or a computer.

After freeing up a few gigabytes, restart the iPhone and see if performance improves before moving to other fixes.

Restart and Force-Quit Background Apps

A simple restart clears temporary memory (RAM) and stops background processes that may be stuck. iPhones are designed to run for weeks without rebooting, but a restart often resolves lag that appeared suddenly.

Press and hold the side button and either volume button until the power slider appears.
Drag the slider, wait for the device to shut down completely.
Press and hold the side button again until the Apple logo appears.

If the phone is frozen and won’t respond, do a force restart (different by model):

iPhone 8 or later: Press and quickly release Volume Up, then Volume Down, then hold the side button until the logo appears.
iPhone 7/7 Plus: Hold both the side and Volume Down buttons until the logo appears.
iPhone 6s or earlier: Hold the Home and side (or top) buttons together.

Also, swipe up from the bottom (or double-click Home) to see open apps, then swipe each one upward to close it. This is not necessary for daily use, but it can help if an individual app is misbehaving.

Update iOS and Your Apps

Apple regularly releases iOS updates that fix bugs and improve performance. Running an outdated version can cause slowdowns, especially if the phone is several years old.

Update iOS: Settings > General > Software Update. If an update is available, tap Download and Install. Plug in power and connect to Wi-Fi first.
Update apps: Open the App Store, tap your profile icon, then scroll to see pending updates. Tap Update All.

If you’re already on the latest iOS, check if Apple has released a minor update (e.g., 17.5.1 after 17.5) – these often contain performance fixes. Also, some apps become sluggish if they haven’t been updated to support the current iOS version.

Reset All Settings (Without Erasing Data)

If the phone is still slow, corrupted settings may be the culprit. Resetting all settings returns preferences (Wi-Fi passwords, wallpaper, notifications) to defaults, but does not delete your photos, messages, or apps.

Go to Settings > General > Transfer or Reset iPhone > Reset.
Choose Reset All Settings.
Enter your passcode and confirm.

After the phone restarts, you’ll need to re-enter Wi-Fi passwords and reconfigure things like Face ID and Apple Pay. This often resolves slowdowns caused by a glitchy network or display setting. If the problem persists, you can try Erase All Content and Settings as a last resort (back up first).

Check Battery Health and Low Power Mode

Apple’s iOS includes a performance management feature that activates if the battery can’t deliver peak power. This prevents unexpected shutdowns but slows the processor. You can see if this is happening:

Settings > Battery > Battery Health & Charging. If “Peak Performance Capability� says your iPhone has experienced an unexpected shutdown, the phone is being throttled.

If your battery’s maximum capacity is below 80%, consider replacing the battery. Apple charges a fee for out-of-warranty replacements, but it’s often cheaper than a new phone. Until then, you can disable the throttle in Settings (if the option appears), but that may cause sudden shutdowns.

Also, turning on Low Power Mode (Settings > Battery) reduces background activity and animations, which can make a slow phone feel faster. It’s a temporary fix, not a solution.

When to Consider a Factory Reset or New Phone

If you’ve tried everything and the iPhone is still painfully slow, a full erase and restore may help. This wipes the device completely, so back up to iCloud or a computer first. Then go to Settings > General > Transfer or Reset iPhone > Erase All Content and Settings.

After the phone restarts, set it up as new (don’t restore from backup) to see if the slowness was caused by corrupted data. If it’s fast, you can restore your backup and see if the problem returns. If it’s still slow even as a fresh phone, the hardware may be aging. iPhones typically receive iOS updates for 5–6 years after release, but performance on older models (like the iPhone 6s or 7) will never match a newer device. At that point, upgrading is the practical solution.

Common Misconceptions and Quick Wins

Many “slow iPhone� articles recommend clearing RAM by holding the power button until the slide appears, then holding Home – this doesn’t work on modern iPhones (no Home button) and isn’t a real fix. Similarly, “closing all apps� daily isn’t necessary; iOS manages memory well. Instead, focus on these quick wins:

Turn off Background App Refresh (Settings > General) for apps that don’t need constant updates.
Reduce Motion (Settings > Accessibility > Motion) to disable parallax and animations.
Delete large attachments from Messages – go to Settings > General > iPhone Storage and tap “Review Large Attachments.�
Reinstall a problematic app – delete it and download it again (data may be lost).

Also, if the phone feels slow only in a specific app, check if that app has a known issue – search the App Store for recent reviews or the developer’s support page.

Frequently Asked Questions

Does a full battery make my iPhone faster?

No, battery percentage doesn’t directly affect speed. However, if the battery is old and can’t deliver peak power, iOS may throttle performance to prevent shutdowns. Keeping the battery above 20% and replacing it when health drops below 80% helps.

Will clearing my iPhone’s cache speed it up?

Clearing Safari’s cache can help if the browser is slow, but there’s no single “clear cache� button for the whole system. Offloading apps and deleting temporary files (like downloaded videos) frees storage, which can improve overall performance.

Why is my iPhone slow after an iOS update?

Sometimes a new iOS version is more demanding, especially on older models. Also, the update process itself can leave temporary files. Try restarting, giving it a day to re-index, and checking for a follow-up update. If it’s still slow, reset all settings.

Is it worth replacing the battery on an old iPhone?

If the phone is otherwise in good condition and you don’t want a new one, yes – a new battery can restore peak performance and may make the phone feel faster. It’s also cheaper than a new phone. Check the battery health first.

How much storage should I leave free?

Apple doesn’t publish a hard number, but keeping at least 10–15% of total storage free is a good rule. For a 64GB phone, that’s about 6–10GB. If you’re constantly near full, consider iCloud storage or offloading unused apps.

Can a slow iPhone be caused by malware?

It’s very unlikely. iOS is sandboxed and Apple reviews apps, so malware is rare. Slowness is almost always due to storage, battery, or outdated software. If you’re concerned, check Settings > Privacy & Security for any suspicious profiles (under “Device Management�) – if you see something you didn’t install, remove it.

General steps for current mainstream versions; menus can differ by device and version. See the disclaimer or report an error.

More in this bed

The whole Tech How-To bed →