If you’re using a VPN and check your internet speeds using a speed test, you may notice that your ping is higher than when you’re disconnected from the VPN. This is especially noticeable when connected to VPN servers on different continents.
Ping is a measure of the transmission time between you and the endpoint, in this case, a speed test server. Ping is measured in ms (milliseconds) with a low ping being ideal. Having a relatively high ping of just one or two hundred milliseconds can make it more difficult to communicate smoothly over a voice or video call and can make online games unplayable.
Ping is primarily affected by the distance your internet traffic needs to travel, specifically the route it needs to take to get there. A VPN increases your ping because it adds extra steps to your internet traffic reaching its destination, making it longer and more complicated. This difference is less noticeable when connecting to a VPN server either near your location or near the location of the server you connect to. This is why it is recommended that you use a local VPN server unless you need to be connected to a specific location, it only adds a small amount of extra difference to any of your web traffic. Conversely using a VPN server halfway around to world to connect to a local web server adds a significant amount of extra distance and travel time to your internet traffic, resulting in you having a higher ping.
In some rare situations, it may be possible for a VPN to actually reduce your ping, but this will generally only affect your connection to a specific site or region rather than your connection to the entire internet. This can be caused by routing differences that can occasionally make the route through your VPN more efficient than directly connecting to the website.