Is Your ISP Throttling Netflix? Find Out How

Is Your ISP Throttling Your Netflix Connection?

Recent news coverage has highlighted a potentially strained relationship between Netflix, the prominent streaming service, and various broadband internet service providers. But can you determine if your ISP is intentionally slowing down your Netflix connection, thereby reducing video quality?

A Reader's Concern

We received a query from a reader, "Netflix Curious," who noticed increased instances of lag, dropped frames, and visual artifacts while streaming Netflix. They questioned whether their internet service provider was deliberately impacting their streaming experience.

Is there a method to definitively test if an ISP is interfering with a Netflix stream?

Testing Your Netflix Connection

Determining direct ISP interference with Netflix bandwidth allocation is challenging to prove conclusively. However, several tests can provide insights into your connection speed to Netflix servers, Netflix’s assessment of your ISP, and a general indication of potential throttling.

Utilizing Netflix's Sample Video Feed

Netflix provides sample video feeds specifically designed for testing your connection and devices. By searching for "example short" while logged into your Netflix account, you’ll find various options showcasing different frame rates and resolutions. We recommend using "Example Short 23.976" for this purpose. (Note: This link requires you to be logged into your Netflix account.)

This 11-minute short film features dynamic scenes within a villa, including movement and stunts. While somewhat abstract, its purpose is to stress-test transmission speeds and frame rates.

Interpreting the Video Readout

When the video loads, a yellow text block appears in the upper left corner, displaying values for BITRATE, RES, and PAR.

These represent the bitrate (transmission speed), resolution (video dimensions as delivered to your device), and pixel aspect ratio (4:3 for standard definition, 1:1 for high definition).

These values correspond to pre-defined streaming rate/resolution/aspect-ratio combinations optimized by Netflix. Here’s a current breakdown of these combinations and their hourly bandwidth consumption (compiled by a home theater enthusiast):

• 2.610 GB per Hour: 25800 Kbps, 1920 x 1080, 1:1
• 1.935 GB per Hour: 4300 Kbps, 1920 x 1080, 1:1
• 1.732 GB per Hour: 3850 Kbps, 1920 x 1080, 1:1
• 1.350 GB per Hour: 3000 Kbps, 1280 x 720, 1:1
• 1.057 GB per Hour: 2350 Kbps, 1280 x 720, 1:1
• 0.787 GB per Hour: 1750 Kbps, 720 x 480, 32:27
• 0.472 GB per Hour: 1050 Kbps, 640 x 480, 4:3
• 0.337 GB per Hour: 750 Kbps, 512 x 384, 4:3
• 0.252 GB per Hour: 560 Kbps, 512 x 384, 4:3
• 0.169 GB per Hour: 375 Kbps, 384 x 288, 4:3
• 0.106 GB per Hour: 235 Kbps, 320 x 240, 4:3

Note that the top three options with 1920 x 1080 resolution are part of Netflix’s SuperHD tier, available on select apps, devices, and content.

Simulating Bandwidth Limitations

Netflix shouldn't limit your connection unless you've set a lower video quality in your account settings. Therefore, any reduction in video quality likely stems from factors between Netflix's servers and your device.

To simulate limited bandwidth, we initiated a large download to reduce available bandwidth and then launched the Example Short test film. The resulting video quality was significantly degraded.

Pausing the download to restore full bandwidth and reloading the video yielded a substantial improvement, reaching the highest bitrate/resolution for a non-SuperHD stream.

The advantage of using Example Short 23.976 is that all benchmarks are handled by Netflix servers, providing a consistent readout across devices.

Further Investigation

If your test results indicate lower-than-expected speeds, consider these additional steps.

Netflix ISP Speed Index

Consult Netflix's ISP Speed Index. Netflix monitors ISP performance and publishes rankings, highlighting those potentially impacting streaming quality. While not definitive proof, these rankings often align with reports of throttling.

Using a VPN

Employing a Virtual Private Network (VPN) can bypass potential ISP throttling. While VPNs introduce some bandwidth overhead, a significant throttling issue should still result in improved video quality as your ISP won't be able to identify your Netflix traffic.

However, switching ISPs or consistently using a VPN are often impractical solutions. Prioritizing Netflix traffic through Quality of Service (QoS) settings on your router can also help, but only addresses issues within your network.

Do you have a tech question? Email us at ask@howtogeek.com and we’ll do our best to provide an answer.