Is your Android phone running slowly? Is the battery drain excessive? Did is used to be better? The problem could be because of apps running in the background. These task killers may help.
Think back to when you first got your new Android phone. Was it fast and responsive? Did the battery last all day? Most probably, so why is it slow and why does the battery expire so quickly now? These problems are caused by apps and the more you install on the phone, the faster the battery dies. Having dozens of apps installed on a phone leads to poor battery life. They require memory and CPU power to run and this impacts the speed of the phone.
iPhone users, read Is iOS draining the battery too fast on your iPhone?
Remove unused apps
The best way to speed up a phone and increase battery life is to uninstall apps. You should take a close look at all the apps installed and ask yourself whether you really need them. For example, instead of having 10 games installed, keep the two you are currently playing the most and delete the rest. You can always install them again.
I sit at a computer all day and so there are few phone apps I really need. I can check Twitter anytime, so it is not needed on my phone. LinkedIn is the same and I only use it on a desktop computer. There are other apps that I don’t really need.
Not everyone sits at a computer all day or is allowed to check Facebook whenever they want, but there will be apps you can remove without losing much. Instead of five news apps, just keep your favourite for example. Trim the fat from your phone and it will run better and your phone will last longer.
The benefits of a task killer
Apps and services running in the background use memory, CPU and battery power. Not all apps run in the background and if they don’t then great, there’s no problem having them on your phone. The problem is that too many apps run in the background and they affect the phone’s performance.
This is where a task killer can be useful because it can stop apps and services running in the background. They often provide a simple button to tap to remove apps from memory and stop them using the CPU and battery. Some can run on a schedule and the result is a cleaner phone with fewer apps running, so it is more responsive and lasts longer between charges.
That’s the theory, but in practice it is not quite so simple.
The problem with task killers
Some apps are designed to run all the time. The system has been set to check if they are not running and to start them if necessary. This means that if a task killer stops an app like this, it will simply restart a minute or even seconds later. They are unstoppable and it’s a waste of time trying.
It isn’t the task killer’s fault and the app developer has set up the app this way. Sometimes there are good reasons for an app or service to be running 24/7, but this is not true of all apps. Some seem to keep running for no obvious reason.
There are many hidden Android system services and even some pre-installed apps bundled with the phone that cannot be removed or stopped. If you try to stop them, they just restart again.
For these reasons, task killers are not perfect and they cannot stop everything. However, they can stop some apps and therefore provide some benefits, but they are not perfect. Here are four that seem to be better than the rest.
Smart Task Killer
Price: Free | By: Ayano | Size: 1.7 MB | Android: 4.03 and up

Smart Task Killer is not the most popular app here, with just 50k+ installs from the Google Play Store, but there are mostly good reviews. It had not been updated for three years when I installed it, but it still seems to work OK, at least on my old Android 7 phone.
Open the app and the home screen shows the amount of memory in use as a live scrolling chart. Below it are the numbers and you can see the used, free and total RAM. A large Optimize button enables you to free up some memory by shutting down apps running the background.
The apps that are killed are listed on the Target tab and checkboxes enable you to choose to keep ones you need. User installed apps, plus some system apps and services are included and Smart Task Killer does free up some RAM when Optimize is used. The app adds shortcuts to the home screen to quickly optimize the phone.
It has some useful settings, such as an option to auto-kill on a regular basis and the time ranges from every 30 minutes to once a day.. It can also be set to optimize only when the screen is off and not when you are using the phone. It keeps a history of optimizations and you can see when auto-optimisation occurred and how much memory was saved.
It is an old app and the benefits from optimizing are not huge, but some improvement is seen. It is ad-supported, but the ads are small and don’t get in the way.
KillApps: Close all apps running
Price: Free | By: Youssef Quadban | Size: 5.0 MB | Android: 4.4 and up

Unlike the previous app, KillApps was updated recently and it has over 1 million installs from the Google Play Store. A good score and good reviews, plus a developer that responds to comments makes this an app worth trying.
KillApps home screen has a large circular graphic and percentage RAM used indicator at the top. You can easily see the amount of memory available and used. Below are a couple of switches and an optimize button. User apps can be closed for free, but closing system apps is a feature in the paid version of KillApps. It’s not expensive.
Swipe up and there is an exception list to which you can add apps that should not be closed. Below that are launched apps, which are apps that have auto-started since KillApp closed them. Further down still, are apps that failed to close when the optimize button was pressed. Right at the bottom is an option to view system apps running in the background.
KillApps is a good app for killing background apps and services. It looks good with dark and light themes available, and is easy to use. The one missing feature is optimization on a schedule. Memory usage creeps up over time and it would be useful to clean the system every so often automatically.
Force Stop Apps (no root)
Price: Free | By: Boot Studio | Size: 3.5 MB | Android: 4.4 and up

Force Stop Apps has 100k+ installs, was recently updated and has a great score of 4.7 in the store. However, that may be for the paid version because the free app has large adverts that will irritate many people. It is cheap to remove the ads, but necessary.
There is a rocket button at the bottom of the screen that is used to optimize the phone and you actually get to see it working. It opens Settings > Apps, opens each running app and auto-presses the Force Stop button.
Apps can be manually added to a list of apps to be closed, but it works on automatic OK. Apps can also be added to an ignore list so they will not be closed.
It does not report the result of optimization, such as the amount of memory made free, but checking in the phone’s Settings showed that it made some good memory savings. There isn’t any scheduling for automatic cleanup, which would be useful.
The free app has ads that irritate, but if you get rid of them, this is a simple and effective task killer.
Task Killer
Price: Free | By: Android Rock | Size: 3.4 MB | Android: 4.1 and up

Task Killer was recently updated and has over one million installs according to the Google Play Store, plus 52,000 ratings giving it a score of 4.4. That is impressive, but I was less impressed by the app than others were.
The app’s home screen is colourful and clear. It displays a memory usage bar at the top and you can see how much RAM is used and the total available RAM. Below this is a list of apps. The problem is that it shows some apps, but it misses a lot. I opened a dozen apps and several just weren’t there for some unknown reason.
It does close the apps it lists, but it misses others that are in the background. It seems a bit limited in what it can do. However, it does have an automatic optimize feature and you can set a timer to clean up at regular intervals. There is also an exclusion list to prevent it from closing apps you want to keep running.
Task Killer looks nice, but it did not seem as effective as the others.
The winner is…
Although only four task killer Android apps were tested here, around 20 were looked at on the Google Play Store. Many were not included because they had not been updated in years, had bad reviews, had changed and become worse (eg. more ads added), and so on.
Among the apps tested here, I liked KillApps best. It looks very nice and it has some good features.