How to Fix iPhone Lagging After iOS 18
If your iPhone feels sluggish after updating to iOS 18, there are several ways to get it running smoothly again. These tips address common causes like background apps, heavy animations, and resource-hungry settings. Here’s how to start:
Method 1: Close Background Apps
Even though iOS handles memory efficiently, having too many apps open can still slow down your iPhone—especially on older models. Swipe up (or double-click the Home button on older devices) to see all open apps, then swipe each app off the screen to close it. This frees up RAM and can improve performance immediatelySwipe up from the bottom of the screen (on iPhones with Face ID) or double-press the Home button (for the iPhone SE 2nd and 3rd generation, as they are the only models with a Home button that support iOS 18) to access the app switcher.
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Swipe through the list of open apps.
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Swipe each app upwards to close it.
Close unnecessary apps to free up system resources, which makes your iPhone run faster. However, this is just the first step. Other factors, such as outdated apps or system settings, can also contribute to iPhone lagging after iOS 18.
Method 2: Clear iPhone Storage
Freeing up storage can make a big difference in performance. iOS 18 itself takes up more space, and leftover files from the update can eat into your available memory, causing lag. To keep your iPhone running smoothly, aim to have 10–20% of total storage free.
Start by checking what’s using the most space: go to Settings > General > iPhone Storage. You’ll see a breakdown of apps, media, and system files along with suggestions for clearing space. From there, you can delete unnecessary apps, old media, or cached data to free up memory and improve responsiveness.
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Open Settings and tap General.
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Select iPhone Storage.
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At the top, you’ll see a storage graph showing how much space is used and how much is free.
If apps are taking up most of your storage, you’ve got a few options:
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If there are apps you don’t need anymore, delete them to free up the space they’re taking, with all their data.
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Offload unused apps. This removes the app itself but keeps its data, so you can reinstall it later without losing anything. To offload it just tap the app and select Offload the App.
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Some apps, especially messaging or social apps, let you clear their cache to free up space without deleting the app. Not every app offers this feature, though, and the settings might look different depending on the app. For example, as you can see in our snapshot, Telegram is taking up a lot of space. In this case, you can go to Settings > Data & Storage within the app and use the Clear Cache option to free up space without deleting your chats or important files.
Next up is the Photos app, which often takes up the largest chunk of storage with all your photos and videos. Manually deleting unwanted media is possible but extremely time-consuming. A smarter approach is to automate the cleanup using a dedicated tool—like the free Clever Cleaner app for iPhone.
We put it to the test and found no paywalls, locked features, or ads—rare for a free app. Clever Cleaner offers features that go beyond what the native Photos app provides, including:
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Find Duplicate & Similar Photos. Unlike the native Photos app, which only identifies exact duplicates, Clever Cleaner uses AI to detect similar images. It finds photos that might look almost identical to the human eye but are actually different. The app groups these similar images together, so you can easily decide which ones to keep and which to delete.
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Identify Screenshots. Clever Cleaner can quickly locate and delete screenshots that often pile up and take up unnecessary space.
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Sort Heavy Files. The app can pinpoint large photos and videos that are eating up storage. This is especially useful for videos, as you can sort them by size from largest to smallest, to identify the biggest space hogs. It’s a handy feature that the native Photos app sadly lacks.
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Compress Live Photos. It can turn a Live Photo into a single still image, removing the extra frames and animations. This can save a lot of space.
Clever Cleaner is fully free, with no restrictions. The developer, CleverFiles, confirms on the official Clever Cleaner cleanup app page that it will remain free for anyone who downloads and keeps it on their iPhone. This trust is reinforced by their track record with Disk Drill, a popular data recovery tool that followed the same model. You can also see Clever Cleaner in action compared side by side with other iPhone storage-cleaning apps in a demo video.
Note: For more storage-saving options, check out our list of the best iPhone cleaners.
Remember, it’s not just apps and photos that consume storage. Check your Mail app, too—attachments like PDFs, images, and other files can quietly accumulate, taking up significant space.
Older iPhones often struggle with System Data, which can occupy a large chunk of storage. We have a detailed guide on how to clear System Data on iPhone to help reclaim that space.
Method 3: Update Problematic Apps
Outdated apps may cause slowdowns after a major iOS update. Developers release updates to ensure compatibility with the latest iOS version. If your iPhone feels sluggish after updating to iOS 18, check for updates—especially for apps that crash or take a long time to open.
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Open the App Store on your iPhone.
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Tap on your profile icon in the upper-right corner of the screen.
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Scroll down to see the updates that are scheduled to be updated. Click Update All or update individual apps that may be troubled.
When you update your apps, you’re guaranteed a seamless experience with iOS 18. If some apps still show poor performance even after updates, it could be due to deeper compatibility issues, which developers may address in future releases.
Method 4: Configure Keyboard Settings
If you notice input lag after the iOS 18 update, your keyboard settings could contribute to the problem. Features like keyboard predictions, haptics, or even third-party keyboards sometimes slow down your iPhone’s response time, especially in apps that rely heavily on text input.
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Go to Settings on your iPhone.
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Scroll down and tap General, then select Keyboard.
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Turn off features like Predictive and Smart Punctuation to reduce processing overhead.
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If you use a third-party keyboard, try switching back to the default iPhone keyboard to see if it improves performance.
When you adjust the keyboard settings, you reduce the load on the phone’s processor, which helps improve response time when typing. This fix often proves effective for those whose iOS 18 makes the phone slow and shows input delays, especially in messenger apps.
Method 5: Disable Dynamic Wallpapers
Dynamic wallpapers add visual effects to your home screen, but they also use more system resources. After the iOS 18 update, this feature can slow down your iPhone, especially on older devices. If iOS 18 is slowing down the phone’s visual effects, switching to a static wallpaper can improve it.
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Open the Settings app on your iPhone.
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Tap on Wallpaper.
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Select Choose a New Wallpaper.
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Scroll to the “Stills” section and select a static image.
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Set it as your new wallpaper for the home screen, lock screen, or both.
After you disable dynamic wallpapers, you can free up system resources that your iPhone would otherwise use for animations.
Tip. For the best performance boost, use one of Apple’s preloaded static wallpapers or a simple solid color.
Method 6: Reduce Interface Motion
The iOS 18 update includes various visual effects that improve the interface, but they also use additional processor power. Some users have reported that after updating to iOS 18, interface animations become “choppy” and experience occasional hangs. Reducing motion effects in the settings can help prevent these performance issues.
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Go to Settings on your iPhone.
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Tap on Accessibility, then select Motion.
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Enable the option Reduce Motion.
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Optionally, toggle off the Auto-Play Message Effects to further reduce animations.
Note. Not only does turning off Auto-Play Message Effects in Accessibility > Motion cut down on lag, but it also helps save battery life.
Method 7: Turn Off the Background App Refresh
Background App Refresh allows apps to update their content in the background, even when you’re not using them. While convenient, this feature consumes system resources, which can slow down your iPhone. iOS 18 may slow down with background app updates enabled, especially after an update, as many apps use this feature to optimize their content for the new iOS version.
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Open the Settings app on your iPhone.
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Scroll down and tap on General, then select Background App Refresh.
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Choose Off to disable Background App Refresh entirely, or select Wi-Fi if you prefer to limit it to Wi-Fi connections only.
Turn off Background App Refresh so your iPhone can focus on system tasks instead of constantly updating apps in the background. Apps will update only when you open them, which might make startup slightly slower, but overall performance will improve.
Is It Possible to Downgrade iOS 18 to 17?
If your iPhone still lags after updating to iOS 18, you might think about downgrading to iOS 17. Unfortunately, Apple no longer signs iOS 17, so an official downgrade isn’t possible. Downgrades are blocked to maintain security and ensure compatibility with apps and features. Unofficial methods exist, but they carry risks—voided warranties, security vulnerabilities, and potential system instability.
Final Words
Battery health also affects performance. A degraded battery can cause throttling and slowdowns. Check your battery status at Settings > Battery > Battery Health & Charging to see if it might be contributing to lag.
For additional help, online communities are invaluable. Forums like Reddit’s r/iPhone, Apple Support, or the InsanelyMac iPhone Forum offer tips, troubleshooting advice, and user experiences that can guide you through any issues.