5 Simple Ways to Know If Your ISP is Throttling Your Internet Speed

The Ultimate Guide to Detecting ISP Throttling: 5 Proven Methods


You‘re in the middle of an important video call when suddenly, the picture freezes and the audio cuts out. You try to load a website, but it takes forever to appear. You pay a premium for high-speed internet service, but lately, it feels like you‘re stuck in the dial-up days. What gives?

If you‘ve noticed seemingly random slowdowns in your internet performance, you may be a victim of a practice known as ISP throttling. Throttling is when your internet service provider (ISP) intentionally slows down your internet speeds for certain types of online traffic or during specific times.

Many ISPs engage in throttling to some degree, often citing the need to regulate network congestion. However, some forms of throttling may cross the line into anti-consumer territory and violate the principles of net neutrality – the idea that ISPs should treat all online traffic equally and not discriminate based on content, user, platform, or application.

Whether your ISP‘s throttling is justified or not, you deserve transparency about the speeds you‘re actually getting compared to what you‘ve paid for. In this guide, we‘ll introduce you to five simple but powerful ways to determine if your ISP is engaging in throttling. By the end, you‘ll be armed with the knowledge and tools to hold your ISP accountable and get the speeds you deserve.

Let‘s start with one of the most straightforward ways to detect throttling – running regular speed tests.

Method 1: Run Regular Speed Tests

The first step in determining if you‘re experiencing ISP throttling is to establish a baseline for your internet speeds. This means testing your speeds at different times of the day and keeping a log of the results.

To run a speed test, you can use a variety of free online tools, such as:

For best results, follow these tips when running a speed test:

  • Use a wired Ethernet connection if possible, as Wi-Fi can be less reliable
  • Close any unnecessary applications and pause any downloads or uploads
  • Run the test multiple times and calculate the average
  • Test at different times of day and different days of the week

Once you have your baseline speeds, you can compare them to the speeds you‘re paying for in your ISP plan. If you notice that your speeds are consistently lower than what you‘re paying for, especially during peak usage times like evenings and weekends, that‘s a sign that your ISP may be throttling your connection.

Here‘s an example of how to log your speed test results:

Date Time Download Speed Upload Speed Ping
01/01 9:00 AM 95 Mbps 10 Mbps 15 ms
01/01 7:00 PM 32 Mbps 5 Mbps 28 ms
01/02 9:00 AM 98 Mbps 11 Mbps 14 ms
01/02 7:00 PM 35 Mbps 6 Mbps 27 ms

In this example, the speeds during peak evening hours are significantly lower than the morning baseline speeds, which could indicate throttling.

Keep in mind that some speed variation is normal due to network congestion. However, if you notice a consistent pattern of slowdowns, especially if they align with certain times of day or online activities, you may be experiencing throttling.

Method 2: Use a VPN to Test for Throttling

If you suspect your ISP is throttling your connection, one way to test this is by using a virtual private network (VPN). A VPN encrypts your internet traffic and routes it through a remote server, masking your online activity from your ISP.

To test for throttling with a VPN, follow these steps:

  1. Sign up for a reputable VPN service. Some of the best VPNs for speed and reliability include:

  2. Download and install the VPN application on your device.

  3. Run a speed test without the VPN connected and record the results.

  4. Connect to a VPN server located close to your physical location. This helps ensure that any speed differences are due to ISP throttling and not distance from the VPN server.

  5. Run the speed test again with the VPN active and record the results.

  6. Compare the speeds with and without the VPN. If your speeds are significantly faster with the VPN, that suggests your ISP is throttling your regular connection.

Here‘s an example of how VPN speed test results could indicate throttling:

Scenario Download Speed Upload Speed Ping
Without VPN 35 Mbps 5 Mbps 27 ms
With VPN 85 Mbps 10 Mbps 18 ms

In this case, the speeds are much faster with the VPN, strongly indicating that the ISP is throttling the non-VPN connection.

However, it‘s important to note that VPNs can sometimes slow down your speeds due to the encryption process. So if your speeds are slower with the VPN, that doesn‘t necessarily mean you‘re not being throttled. It‘s best to choose a VPN known for high speeds and run multiple tests to confirm the results.

Method 3: Monitor Your Data Usage and Speeds

Another common tactic ISPs use is data deprioritization, where they slow down your speeds after you‘ve used a certain amount of data in your billing cycle. To determine if you‘re experiencing data deprioritization throttling, you‘ll need to monitor both your data usage and your speeds.

First, check your ISP plan details or contact customer support to see if your plan has any data caps or thresholds where deprioritization kicks in. Many plans have limits like 1 TB per month.

Next, track your data usage throughout your billing cycle. You can usually do this through your ISP account portal or by consulting your monthly statements. Keep an eye out for any patterns where your speeds slow down after hitting a certain level of data usage.

For example, let‘s say your plan has a 1 TB data cap before deprioritization. Here‘s how you could track your usage and speeds:

Date Data Used Speed Test Result
01/01 200 GB 95 Mbps
01/15 600 GB 90 Mbps
01/25 1.1 TB 35 Mbps
01/31 1.5 TB 30 Mbps

In this scenario, you can see that the speeds drop significantly after exceeding 1 TB of data, indicating deprioritization throttling.

If you do identify a data usage threshold where throttling begins, you can try to reduce your data consumption to stay under that limit. Some tips include:

  • Lowering video streaming quality
  • Limiting large file downloads
  • Turning off automatic updates for apps and operating systems
  • Using data compression in your web browser

You can also consider upgrading to a plan with a higher data cap or with truly unlimited data, although this will likely come with a steeper monthly cost.

Method 4: Test Speeds for Specific Sites and Services

In some cases, ISPs may throttle speeds only for certain types of content, like streaming video or peer-to-peer file sharing. This is known as content-based throttling.

To check for content-based throttling, you can run speed tests while connected to specific sites or services and compare the results to your baseline speeds.

Some commonly throttled sites and services include:

To test for content-specific throttling, follow these steps:

  1. Run a baseline speed test not connected to any specific site and record the results.

  2. Connect to one of the potentially throttled sites or services and start streaming or downloading content.

  3. While the content is loading, run another speed test and record the results.

  4. Repeat the process for each site or service you want to test.

If you notice that your speeds are significantly slower when connected to certain sites compared to your baseline, that‘s a sign of content-based throttling.

For example, imagine you pay for a 100 Mbps plan and get the following speed test results:

Scenario Download Speed Upload Speed
Baseline 95 Mbps 10 Mbps
Netflix 35 Mbps 10 Mbps
YouTube 90 Mbps 10 Mbps
Spotify 95 Mbps 10 Mbps

These results show a clear slowdown when connected to Netflix, but not the other services, strongly suggesting Netflix is being specifically throttled.

You can also cross-reference these results by running the same tests with a VPN active. If your Netflix speeds are still slow with the VPN, the issue may be with your home network setup or the VPN itself rather than ISP throttling.

If you do identify content-specific throttling, you can try contacting your ISP to ask about their policies and express your concerns. You can also file a complaint with the FCC if you believe the throttling is unjustified and anti-consumer.

Method 5: Check for Throttling by Port

A more technical way that some ISPs implement throttling is by slowing down traffic on specific network ports commonly used for high-bandwidth activities like online gaming, video streaming, and file sharing. This is known as port throttling.

Some commonly throttled port numbers include:

  • TCP Port 1935 (used for video playback)
  • TCP Port 3128 (used for web caching and proxies)
  • TCP Ports 6881-6999 (used for BitTorrent traffic)

To check for port throttling, you can use an online port scanner tool like YouGetSignal (https://www.yougetsignal.com/tools/open-ports/) or CanYouSeeMe (https://canyouseeme.org/).

Here‘s how to check for port throttling:

  1. Choose a port number you want to test based on your most-used online activities.

  2. Enter the port number into the port scanner tool along with your IP address (which the tool will usually auto-detect).

  3. Run the port scan and check the result. If the port is "closed" or "blocked," your ISP may be throttling traffic on that port.

  4. Repeat the process with a VPN connected. If the port shows as "open" with the VPN but "closed" without, that strongly indicates ISP port throttling.

However, port scanning has some limitations. Even if a port appears closed, that doesn‘t always mean it‘s being throttled – it could simply be closed by your operating system‘s firewall. Additionally, ISPs can use more sophisticated methods to throttle traffic without completely blocking ports.


We‘ve covered a lot of ground in this guide, diving deep into five key methods you can use to detect ISP throttling:

  1. Running regular speed tests
  2. Testing speeds with a VPN
  3. Monitoring data usage and speeds
  4. Testing speeds for specific sites and services
  5. Checking for throttling by port

By trying a combination of these techniques, you‘ll be well-equipped to gather evidence and determine if your ISP is engaging in throttling. Remember, throttling isn‘t always clear-cut – you may need to run multiple tests and document your findings over time to identify patterns.

If you do conclude that you‘re experiencing unjustified throttling, don‘t hesitate to take action:

  • Contact your ISP to express your concerns and ask about their throttling policies
  • File a complaint with the FCC if you believe the throttling violates net neutrality principles
  • Consider switching to a different ISP with more consumer-friendly policies

At the end of the day, you deserve the internet speeds you pay good money for. Throttling may be a reality of our current digital landscape, but that doesn‘t mean you have to accept it lying down. Armed with the knowledge and techniques from this guide, you have the power to hold your ISP accountable and advocate for a more open, transparent internet.

So go forth and start testing, and together, we can work toward a future where ISP throttling is a thing of the past. Your streaming video binges and gaming sessions will thank you.