VPNs and Data Usage

There’s a lot we can do with a VPN. We can access geo-blocked content, sidestep internet censorship, and become truly anonymous online.

Unfortunately, there is also plenty of confusion about the way VPNs work. And one of the most commonly misunderstood topics is around the impact that a VPN has on data use, including any ISP or wireless carrier imposed data caps.

Will using a VPN count against your data limit? Can you use one to get around those caps? Those are questions I so often hear.

To help demystify this issue, here’s a guide to everything you want and need to know about VPNs and data usage.

What Is a VPN?

Before we dig deeper, we need to understand the basics. A VPN, or virtual private network, is a software solution which creates a network-within-a-network. It privatizes and hides from the outside world data traffic passing to and from your device.

A typical VPN setup starts with the installation of client software on your device. That software then establishes an encrypted tunnel to a server run by the VPN provider. All your outgoing and incoming traffic will then use that tunnel to reach the wider internet.

Depending on the type of encryption that a VPN service uses, it can be impossible (or at the very least exceedingly difficult) for any 3rd-party to intercept and view your information.

Some VPN providers also disable traffic logging. They ensure there is no record kept of what traffic belongs to which user of their system. In these cases, the VPN provides you with near-perfect anonymity and excellent protection of all your data.

Does a VPN Use Data?

A VPN, like any other internet-connected resource, does send and receive data. It relies on an existing internet connection to provide the route between your device and the VPN server. That means that your ISP can and does still count any traffic which passes over the VPN towards any general data caps or restrictions.

Looking into how much extra data a VPN uses

What your ISP can’t do when you use a VPN, however, is to see the contents of your internet traffic.

That means that they won’t be able to apply any limits or throttling based on what service you’re using. This makes a VPN a particularly useful tool if you have found that specific services (like BitTorrent or Netflix) are speed restricted by your ISP.

Does a VPN Increase Data Usage?

When you are using a VPN, your data usage will increase. The encryption that a VPN applies to keep the connection secure will generally grow the size of the transmitted data anywhere from 5%-15%.

Most commercial VPN providers make use of compression to try to offset the overhead. And though providers like CyberGhost VPN are doing a better job of it than others, it’s mostly a losing battle.

While compression can occasionally decrease the size of the encrypted data, most types of internet data don’t compress well. For example, traffic to and from an SSL-secured website (HTTPS) is typically compressed already by the web server the site lives on. That means that the VPN’s built-in compression will have little to no effect on it.

The same is true for streaming video and almost every other kind of internet traffic. The one exception is simple, unsecured text (but really, how much of that do we send these days).

Which VPN Protocol Uses the Least Data?

Although any encryption will increase data size, not every encryption standard is created equal.

If you’re concerned with keeping overhead at a minimum, choose the standard wisely. It will make a difference.

Most VPN providers offer the same handful of encryption options. Here is a list of those standard types, ordered from least data usage to most:

  • 128-bit PPTP – Low Data Use, Poor Security
  • 128-bit L2TP/IPSec – Low Data Use, Moderate Security
  • 128-bit OpenVPN – Low Data Use, Moderate Security
  • 128-bit Stealth OpenVPN – Moderate Data Use, Moderate Security
  • 256-bit L2TP/IPSec – Moderate Data Use, Excellent Security
  • 256-bit OpenVPN – Moderate Data Use, Excellent Security
  • 256-bit Stealth OpenVPN – High Data Use, Excellent Security

As you can see, PPTP encryption is the most data efficient. However, it’s important to note that it is considered to be insecure and therefore should pretty much be avoided. Most VPN providers only support PPTP to maintain good compatibility across different devices.

The 128-bit and 256-bit stealth options also stand out. They use SSL encapsulation to make it seem like the VPN traffic is nothing but standard HTTPS traffic. While this does help to avoid VPN restrictions (be it by your school, ISP or even at the government level), it will also increase the data size.

The Protocol to Pick

For the average internet user, choosing 128-bit OpenVPN encryption provides the perfect mix of security and low overhead.

For all practical purposes, the type of encryption used by the OpenVPN protocol is currently unbreakable even with 128-bit keys. But if you opt for any 256-bit option, do note that the additional security come at a cost.

Encryption which makes use of 256-bit keys will perform on average about 40% slower than the same encryption type using 128-bit keys. That’s far from insignificant. Even if you’re using one of the fastest VPN providers, the difference will be noticeable. It’s an especially important factor to consider if you’re using your VPN for applications where speed matters, like streaming video.

Does Using a VPN Count Against Data Caps

As mentioned earlier, a VPN does rely on your ISP to send data to and from the internet. Even though your ISP cannot determine what it is you are doing online via your VPN connection, they can measure the amount of data that is passing through their network.

In other words, using a VPN will count against any data caps that apply to your regular internet service.

In fact, because a VPN increases the size of the data you send over your internet connection, you may find that your data cap becomes even more restrictive.

Trying to use a VPN to get around mobile data caps

Of course, not every data cap works in the same way. Some ISPs (or wireless providers) sell data packages that include a pre-set amount of data transfer. If you run out, you cannot use your internet service until you purchase another block of data.

Others do not disconnect you when you reach the pre-set limit. They instead drop your connection speed until your billing cycle completes or you purchase more data. In the case of the latter, your VPN will continue to function, but with reduced performance.

Can a VPN Bypass Data Caps?

Many people explore VPN services as a means of bypassing data caps set by their ISP or wireless provider.

As noted above, a VPN relies on your ISP to send data to the internet. So, avoiding the ISPs data caps is not possible – at least in most cases.

The only time a VPN may help you avoid a data cap is when the ISP restricts data based on the type or destination of the data itself.

ISPs and Data Inspection

Late last year Verizon Wireless users started to notice that their access to Netflix was far slower than other online services. It turned out that Verizon had been intentionally restricting connection speeds to the video streaming service.

Users speculated that Verizon was preparing to introduce a tiered data system. In doing so, they would show preference to specific services, while crippling others.

Although Verizon didn’t push things further (at least for now), it’s a perfect example of a situation when a VPN could be useful in avoiding ISP restrictions on specific sites and services.

With a VPN, Verizon wouldn’t have been able to detect that the traffic was destined for Netflix. It, therefore, couldn’t have counted it against any Netflix specific data or speed caps.

With the countdown to the death of net neutrality in the United States underway, ISPs could begin throttling and blocking data in this way in the very near future. Using a VPN may be one of the few options most of us will have to get around that.

Data is Data, Even on a VPN

VPNs are an excellent tool to improve your privacy and security online. They won’t, however, decrease your overall data usage. In fact, every VPN provider is almost guaranteed to marginally increase how much data you use, no matter how you configure it.

Where a VPN should help, however, is in getting around data caps or throttling imposed by your ISP on a specific service, like Netflix or torrents.

Give it a try and see what happens. All top VPNs offers at least a 30-day refund policy (and some go as high as 45 days). If you find it’s not working, cancel the service for a full refund. Although, after you experience the extra privacy, online freedom, and streaming benefits you get with a VPN, you may just end up keeping it anyway.

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About Tim Tremblay

Tim is the founder of Fastest VPN Guide. He comes from a world of corporate IT security and network management and knows a thing or two about what makes VPNs tick. Cybersecurity expert by day, writer on all things VPN by night, that’s Tim. You can also follow him on Twitter and Quora.

5 thoughts on “VPNs and Data Usage”

  1. I’m looking to know how much data will be used on a VPN network connection per hour using Windows Remote Access app. Is that something that can be calculated?

    • Hi Michelle,

      You should be able to get a ballpark estimate, but the numbers can vary significantly depend on what you’ll be doing. Things like screen resolution, what’s shown on the screen (ex: static vs dynamic content), file downloads, etc. will all affect how much data you use. I’ve seen RDP use as little 10MB per hour and in excess of 1GB per hour on the other extreme.


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