What is a Kill Switch?

Hand pressing red button on a dark background
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Kill switch: a summary

A kill switch is an emergency stop. This function with most VPNs’ software automatically blocks all internet traffic if your VPN’s connection drops. This way, your data will remain safe, secure and anonymous.

A trustworthy VPN with a good kill switch is ExpressVPN. Press the button below if you want to give this provider a try.

Want to know more about the kill switch, how it functions exactly, and why it might be a good idea to choose a VPN that has one? Read the article below to find out all that and more.

If you’re interested in VPNs or have read some of our reviews, you’ve most likely come across the term “kill switch”. The kill switch is often considered a big advantage of any VPN provider that offers one. Still, many of our readers don’t seem to know exactly what a kill switch does and why it’s better to use one. Therefore, you can read all about the kill switch down below.

What is a kill switch?

Kill Switch OffIn the most general sense of the word, a kill switch refers to a mechanism that causes a machine to abruptly turn off when something goes wrong. It can also be used to describe a similar emergency stop in software instead of physical machinery.

If a machine breaks down, crashes, or starts acting up in any other way, the kill switch can be used to shut it down immediately. Most kinds of heavy machinery have a switch like this for protection. As you might imagine, a kill switch is essential to any machine with drills or saws that might endanger its users when out of control. Kill switches often appear as bright red buttons on these machines, so they’re easy to find. With this one button, you’ll be able to avoid dangerous situations right away. Not only heavy machinery but also some vehicles and elevators have an emergency button that functions as a kill switch. This function is always added to guarantee the user’s safety.

A kill switch for software 

Same as with machines, some software also makes use of a kill switch. Think, for example, of software used by big companies that collect a lot of user data, or government software containing all sorts of sensitive information. If the software ends up in the hands of unauthorized people, a kill switch can make sure they won’t get to see any of this sensitive data. Without the right authorization, the person trying to get access to the information won’t get it. The data will be made invisible or inaccessible. The kill switch could even completely delete the software. This way, any sensitive information stays out of the wrong hands.

Kill switches can also be used in other contexts. Smartphones tend to use them to discourage stealing. Since the kill switch can make the device completely unusable, it’s much less likely that thieves will waste their time trying to steal it. Some Windows, Google, and Apple smartphones also have a kill switch to ensure the safety of installed apps. If an app on the phone is infected with harmful software, the kill switch can instantly isolate and stop that app. This prevents further infection and keeps the rest of the device safe. Moreover, the harmful software can be removed immediately.

Why do VPNs have a kill switch?

Most people that use a VPN, do so to protect their privacy. They wish to stay anonymous while browsing the internet, and a VPN can help with that. If your VPN were to temporarily malfunction, however, you’d be left unprotected. Your data will be sent onto the internet without the added protection of a VPN tunnel. As a result, your IP address will be visible to the outer world anyway. This is where the kill switch comes in.

A VPN kill switch ensures you’ll never go online unprotected. If your VPN malfunctions while you’re browsing, the kill switch will shut down your connection to the internet altogether. For as long as the VPN suffers from connection issues, you won’t be able to browse, stream, or download anything. Since your entire internet connection is put to a stop, your real IP address will remain protected and your privacy will stay intact. Hackers won’t be able to get to your data. In other words, the kill switch ensures that the VPN protects you, even when it doesn’t work quite as it should. The picture down below illustrates how this works.

Kill Switch VPN Illustration with hacker

Why would my VPN connection drop?

A dropping VPN connection can have multiple causes. Here are some of the most frequent ones:

  • Bad internet connection: If you’re working with an unstable internet connection to begin with, chances are your VPN might falter. This could be the case when you’re using a Wi-Fi network with a weak signal, for example. Constantly switching between networks has a similar effect.
  • Problems with the VPN server: Another possible cause is the VPN server itself. If a server is experiencing some kind of internal malfunction, this can cause your VPN connection to drop in its entirety. Issues could be caused by the server’s signal strength, disruptions in the physical server, or simple time outs of the connection. Moreover, when a particular server is being used by many people at the same time, it becomes overcrowded. At these times, problems often occur as well: the connection can become incredibly slow or drop altogether.
  • Firewall, antivirus or router settings: Another possible hindering factor could be hiding in the settings of other programs on your device. Some programs have specific settings that, when activated, won’t allow your VPN to set up a connection. A firewall or antivirus program could see the VPN’s external connection as a risk. As a result, they’ll try to stop the VPN, turning your secure tunnel into an irregular and untrustworthy connection. Even your router and your device’s automatic updates could cause issues of this kind.

Which VPNs have a good kill switch?

What to Look for When Choosing a VPN iconIn general, people consider a kill switch a positive addition to any VPN service. Due to its very nature, an activated kill switch could stop you from going online for a certain period of time. However, in most cases, this beats the alternative: being unprotected on the internet. The kill switch increases your online privacy and helps you keep control of your internet connection.

Many VPNs have a kill switch. Some providers require you to turn it on by hand by changing the settings, while other providers have activated it as a default. Some VPN providers are better than others, however. For that reason, we’ve listed two of the best VPN providers that offer a kill switch down below.


Screenshot of ExpressVPN website page with added logo in the bottom right corner

For quite a while now, ExpressVPN has topped our list of best VPNs of the moment. Their kill switch is called the ‘Network Lock’ and is available for Windows, Mac, Linux and all routers (through their app). If your connection drops, the Network Lock will notice and instantly cut off all communication with the internet. The Network Lock will make sure none of your personal information is sent out until ExpressVPN has successfully restored the connection to the server. At that moment, the Network Lock will allow data traffic to be sent through again. Aside from a good kill switch, ExpressVPN also has fast servers, is very user-friendly, and works with Netflix.

Great discount on annual subscription + 30-day money-back guarantee!
  • Very easy to use VPN
  • Perfect for anonymous browsing, downloading, and streaming (i.e. Netflix)
  • 3000+ servers in 94 countries
Visit ExpressVPN


Screenshot of NordVPN website homepage with added logo in the corner

NordVPN is another consistent and reliable option. This VPN provider’s kill switch works on Windows, macOS, Android and iOS. The option has been integrated into the software and is easy to switch on and off. NordVPN recommends that users use the kill switch as much as possible. The company sees it as a last line of defense. Moreover, NordVPN allows users to set up ‘kill-lists’, in which you can include apps you don’t want to be blocked in case of a time out. This way, you’ll be able to access some programs even when the kill switch has been activated and the VPN connection drops. In general, NordVPN has an extensive server network and is relatively cheap. It even works when you’re outside of the USA and want to watch American Netflix.

Our pick
Our pick
Only $2.99 a month for a two-year subscription with a 30-day money-back guarantee!
  • Excellent protection and a large network of servers
  • Nice and pleasing application
  • No logs
Visit NordVPN

Final Thoughts

A kill switch, or emergency stop, is a useful software feature that helps protect the user. When speaking of a VPN kill switch, it means that your information remains safe even when the VPN software malfunctions and your protected connection falls away. You won’t be able to go online unprotected and sites won’t be able to discover your real IP address. If you’re looking for a VPN with a kill switch, we’d like to refer you to either ExpressVPN or NordVPN. These VPN providers will definitely help you stay safe! You should also consider going for a VPN and an antivirus combo to really protect your computer and your online presence.

Tech journalist
Tove has been working for VPNoverview since 2017 as a journalist covering cybersecurity and privacy developments. She has broad experience developing rigorous VPN testing procedures and protocols for our VPN review section and has tested dozens of VPNs over the years.