What a speed test measures and why it matters
A speed test measures three things: how fast data travels to your device (download speed), how fast data travels from your device (upload speed), and how long it takes for your device to reach a server and get a response back (ping or latency). These numbers tell you whether your internet connection matches what you pay for, whether your connection is stable enough for video calls or gaming, and whether a problem is on your end or your provider's.
Speed tests work by sending a file to a test server, measuring how long the transfer takes, then doing the reverse. The results come back in megabits per second (Mbps) for download and upload, and milliseconds (ms) for ping. A speed test takes about one to three minutes and uses a small amount of your monthly data.
Key Takeaways
- Speedtest.net, Fast.com, and Google's built-in speed test are the most common free tools and give similar results.
- Run the test on a device connected by ethernet cable for the most accurate reading of your actual internet speed.
- Close other programs and browser tabs before testing, because downloads, streaming, or uploads in the background will lower your numbers.
- If your speed is much lower than what you pay for, restart your modem and router, then test again before contacting your provider.
- Ping matters most for online gaming and video calls; download speed matters most for streaming and browsing.
Running a speed test on Speedtest.net
Speedtest.net is the most widely used speed test tool. Go to speedtest.net in any web browser, and you will see a large blue button labeled "Go". Click it. The test will automatically select a nearby server and begin measuring. You will see the download speed appear first (usually taking 30 to 60 seconds), then the upload speed, then the ping. When all three numbers appear, the test is complete.
Speedtest.net also shows your IP address and the name of the server it used. If you want to test against a different server — for example, one farther away to see if distance affects your speed — click "Change Server" before clicking Go. The results page includes a "Share" button that generates a link to your results, useful if you need to show them to your internet provider.
Using Fast.com and Google's speed test
Fast.com is Netflix's speed test tool and requires no clicking. Go to fast.com and the test starts automatically. It shows only download speed, which is what Netflix cares about most. The test finishes in 30 seconds or less. If you want to see upload speed and ping as well, click "Show More Info" after the download number appears.
Google's speed test appears when you search "internet speed test" in Google Search. Click the blue "Run Speed Test" button and Google will measure your download speed, upload speed, and ping using a nearby server. The test takes about one minute. Google's tool is simpler than Speedtest.net and shows fewer options, but the results are reliable for a quick check.
Getting accurate results: ethernet, timing, and background activity
Speed test results are most accurate when your device is connected to your modem by an ethernet cable rather than Wi-Fi. Wi-Fi speed varies based on distance from the router, interference from walls and other devices, and how many devices are connected. If you test over Wi-Fi, you are measuring your Wi-Fi speed, not your internet speed. If you cannot use ethernet, test from the same room as your router and as close as possible.
Run the test when no one else in your home is using the internet. Downloads, streaming, video calls, or online gaming on other devices will consume bandwidth and lower your test results. Close all browser tabs except the speed test tab, and close programs that might be updating or syncing in the background — common culprits are cloud storage apps, email clients, and operating system updates.
Test at different times of day if your results seem inconsistent. Internet speed often drops during evening hours when more people in your area are online. If you see a big difference between morning and evening speeds, that is normal. If speeds are consistently low at all times, the problem is likely with your connection or your plan.
Understanding your results and what the numbers mean
Compare your results to the speed you pay for. Your internet bill should list a download speed — often something like "100 Mbps" or "500 Mbps". Your test result should be close to that number, usually within 10 percent. If you pay for 100 Mbps and consistently see 90 Mbps or higher, your connection is working as promised. If you see 50 Mbps or lower, something is wrong.
Upload speed is usually much lower than download speed — this is normal. Most home internet plans offer 5 to 20 Mbps upload even when download is 100 Mbps or more. Upload speed matters if you video call, upload videos, or work from home with large file transfers. For basic web browsing and streaming, upload speed rarely matters.
Ping is measured in milliseconds and lower is better. Ping under 50 ms is excellent. Ping between 50 and 100 ms is good for most uses. Ping above 100 ms can cause noticeable lag in video calls and online games. Ping is determined by your location and your provider's network, not by your plan speed, so you cannot upgrade to lower ping the way you can upgrade to faster download speeds.
What to do if your speed is lower than expected
If your test shows speeds much lower than what you pay for, restart your modem and router before assuming there is a problem. Unplug the modem from power, wait 30 seconds, and plug it back in. Wait two minutes for it to fully restart. Then unplug the router, wait 30 seconds, and plug it back in. Wait another minute, then run the speed test again. A restart often fixes temporary slowdowns.
If speeds are still low after a restart, check whether you are testing over ethernet or Wi-Fi. If you tested over Wi-Fi, move closer to the router or test with an ethernet cable. If you tested over ethernet and speeds are still low, try a different speed test tool to confirm the result. Different tools sometimes show slightly different numbers.
If multiple tests over ethernet show speeds 25 percent or more below what you pay for, contact your internet provider with your test results. Provide the download speed, upload speed, and the name of the server you tested against. The provider can check whether there is a problem on their end or whether your modem or router needs replacement.
Speed test tools beyond the main three
Ookla, the company behind Speedtest.net, also runs Speedtest apps for phones and tablets. These apps test your Wi-Fi or mobile data speed and save your results over time so you can track whether your speed is getting worse. The app is free and works the same way as the website.
Your internet provider may have its own speed test tool on their website. These tests use the provider's own servers rather than third-party servers, so they sometimes show higher speeds than Speedtest.net or Fast.com. Provider tests are useful for checking whether the problem is with your connection to the provider's network specifically, but third-party tests are more reliable for comparing your actual speed to what you pay for.
Frequently Asked Questions
How much data does a speed test use?
A single speed test uses about 100 to 750 megabytes of data, depending on the tool and how long the test runs. If you run one test per week, that is roughly 400 megabytes to 3 gigabytes per month — a small fraction of most home internet plans. Running a speed test will not cause you to hit a data cap.
Why do I get different results on different speed test tools?
Different tools use different servers and measure slightly differently, so results vary by 5 to 15 percent. Speedtest.net, Fast.com, and Google's test usually give similar results. If one tool shows much lower speeds than the others, that tool may be using a server farther away or experiencing congestion. Run the test on at least two different tools to confirm your speed.
Does running a speed test slow down my internet for other devices?
Yes, while the test is running, it uses your full bandwidth and will slow down other devices. Close the test when it finishes. If you need to run a speed test while other people are using the internet, ask them to pause streaming or downloads first, or run the test at a time when no one else is online.
What speed do I need for streaming video?
Netflix recommends 5 Mbps for HD video and 25 Mbps for 4K. YouTube recommends 2.5 Mbps for HD. Most people see good results with 25 to 50 Mbps download speed. If you have multiple people streaming at the same time, add 25 Mbps for each additional stream.
Can I test my phone's internet speed the same way?
Yes, but the result measures your Wi-Fi speed or mobile data speed, not your home internet speed. Open Speedtest.net, Fast.com, or Google's speed test in your phone's browser and run the test the same way. For the most accurate result, test over Wi-Fi from the same room as your router, or test your mobile data by moving away from Wi-Fi.