How to measure your true Internet speed

Woody Leonhard

Curious about your Internet speed? Most Internet service providers (ISPs) offer some sort of throughput test tool on their sites — just click, and you’ll get a couple of often-impressive numbers.

It’s in an ISP’s interest to provide the best speed numbers possible; your actual throughput is probably something quite different.

Understanding the nuances of Internet speed

Let’s start with a few basics. In most cases, consumers measure Internet speed three ways: download speed, upload speed, and/or latency/ping time. Download and upload speeds are usually reported in bits per second — typically, kilobits per second (Kbps) for slower connections and megabits per second (Mbps) for faster connections. (Extremely fast connections might also be measured in gigabits or terabits. has a handy online tool for converting transfer units.)

Almost all Internet speed–testing sites measure how long it takes to download one file over one connection from a webserver to your PC. Depending on where and how you download most files, that might be an accurate reflection of your average throughput.

However, all major browsers have download accelerators built in. (Free, third-party accelerators are also available as browser add-ons.) Accelerators typically download files over two or more connections — often without any indication to browser users. That makes it impossible to predict whether an accelerator is delivering a faster download — and how much faster that delivery might be.

Torrents (used for downloading large files; more info) take multiple data streams as an article of faith. So your typical Internet speed test probably won’t provide an accurate measure of torrent download speeds, which depend on mostly uncontrollable factors such as the number of sites (or seeds) offering the file for download and the speeds of those seeding sites. (This assumes your ISP doesn’t block torrents — more about that later.)

As with download-speed tests, upload tests measure how fast it takes to send one file over one connection from your PC to the cloud. Depending on your Internet service, upload speed can be one-third to one-tenth your download speed. (For example, the “A” in an “ADSL” connection means “asymmetric” — which, in almost all cases, is optimized for downloads at the expense of upload speeds. Some services — typically for business — provide similar upload and download speed.)

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All Windows Secrets articles posted on 2012-12-06:

Woody Leonhard

About Woody Leonhard

Woody Leonhard is a Windows Secrets senior editor and a senior contributing editor at InfoWorld. His latest book, the comprehensive 1,080-page Windows 8 All-In-One For Dummies, delves into all the Win8 nooks and crannies. His many writings tell it like it is — whether Microsoft likes it or not.