Line Speed Test (up to 3 Mbps Internet Connection Testing)

Test by Cristian Francu (

Test your Internet connection to this server! Try this applet and check your line speed. This test may take 4 minutes in order to be accurate, so please be patient.

This server is located in Atlanta, GA

This is work in progress, I'm still testing the applet.

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How does this page work?

General description

The panel on the left is an applet, a small piece of code that runs inside your browser. The applet talks to our server machine exchanging data, trying to determine the speed of your line. To measure the upload bandwidth the applet sends data to the server, which times it and computes the speed. To measure the download speed, the server sends data to the applet, which measures the speed locally.

Using the applet

  • Choose a name and login. It would be nice if you used the same name every time, for my own statistics. We don't necessarily need your real name. We don't need your name at all, but in case you ever want to email me you can just say look, I ran your test and it went so wrong, can you tell me why, my test name was Speedy. Before emailing me make sure you read this page, especially the troubleshooting and FAQ section.
  • Push the TEST button and wait faithfully for the results to show up :-)
  • If you suspect the results are not quite accurate use the KEY button (second button in the upper left corner) to adjust the pumping speed. There you can tell the applet at what rate to send data upstream or downstream. The speeds should be the ones you expect, or slightly higher. If you want to learn more about this feature read the Details section further down. After setting the speeds push the login button to login again. The applet will be remember the new speeds. At the moment the default pumping speeds are 600kbits/sec upload and 3mbits/sec download. Hence, if you have a better connection you MUST change these speeds.

What do the results mean?

We run 4 upload tests and 4 download tests and report the best measurement. The results are probably among the most accurate you can get without installing special software. However, if your Internet connection to the speedtest server is bad you might get small speeds. This doesn't mean that you have a bad connection to Internet, but that you have a bad connection to my server. The nice part is that if you do get good numbers, that means that your connection to Internet is good, there is no other way.

Do not pay much attention to the packet loss data. Since we are pumping data at higher speeds than your line speed it is only normal to have dropped packets. This does not mean that you have a faulty connection. However, once you ran the test and found out your line speeds, if you input those speeds using the KEY button and run the test again you should get close to 0% packet loss. If after adjusting the speeds you still have significant packet loss (> 20%) then you might want to ask your ISP to test your line.

Troubleshooting and FAQ

  1. I get a 'Communication failure, server not responding' error

    Most people get this error when measuring the downstream speed. A common cause for that is that your network connection is protected by a firewall, a computer that filters the packets that are coming towards your computer. Since we are using UDP packets, if they get blocked the applet never gets an answer from the server. Fortunately, a firewall means that you are probably running this test from work (shame on you, you should be working!), which means you probably already have a good connection and are running the test just for fun.

    If you have DSL at home and get this error then something is wrong (to my knowledge DSL providers do not block packets). Maybe you have your own setup on your local network that blocks UDP packets? If not, or if you don't even know what I'm talking about, you might want to ask your DSL company about this.

  2. Why is my packet loss so high?

    Normally you don't need to worry about that. We rush so much data down your line that some of it gets lost. That number only tells you how much faster than the actual line speed we are pumping packets.

    The only time you might want to take this number into consideration is when you set the speeds to the actual line speeds using the KEY button. If you still get big packet loss than this might mean that your line is faulty.

  3. Why do I get a much lower upload or download speed, my provider told me it should be higher

    There can be many reasons why this happens:

    • Your computer is far from my server
      Look at the top of the page to see the location of this server. If you are half the country away from it this is likely the reason.
    • You expect too much
      Read the fine print of your provider. While they promise speeds like 1.5mbps, they usually only guarantee 384kbps, depending on your distance from the switch. Go to to find it out (they'll ask you for your zip code and street address). If you are more than 11,000 feet from your CO than you should expect something closer to the min rather than the max :-( Also, don't forget that the upload speed is usually much smaller then the download speed, with ADSL. Combinations of 1.2mbps download and 100kbps upload are common.
    • You have a very high speed connection
      The current version of this test currently measures speeds up to 600kbps upload and 3mbps download. If you believe either one of your line speeds is higher than that then go to the section 'Using the applet' and read about the speed adjustment feature, where you'll learn how to increase the pumping rate of the applet to measure even higher speeds. The applet was somewhat tested with speeds up to 50mbps and seemed to work fine.
    • Something is actually wrong with your line
      If you are quite sure that none of the previous reasons apply, then call your ISP and ask them.

Reporting Errors

I hope this tool will be useful to people. If you feel this is, or could be useful to you, here is how you can help: if you notice any strange behavior, or if you suspect the measurements are not accurate, email me describing the problem. I want to make it useful on a wide range of types of connections and I know it's not working in all situations, but I can't figure out those cases because they're rare. Once I have a database of sites that don't work I can maybe improve it further.

First, make sure you read the troubleshooting section: maybe the answer to your question is there. If you still believe the measurement results are inaccurate, please email me with the following information: login name, the download and upload speed you expected, and the rates at which you set the tool to send data, in case you modified them on the options panel.

Details for the curious

Yet to come, curious people hold your breath

Back to Cristian's page

Last update: Feb 13th, 2007
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