What you're actually measuring when you run a speed test
A speed test measures how fast data moves between your device and a server on the internet, usually in megabits per second (Mbps). The test sends a file to that server and back, timing how long it takes. What you get back are three numbers: download speed (how fast data comes to you), upload speed (how fast data goes out from you), and ping (how long it takes for a signal to reach the server and come back, measured in milliseconds).
These numbers tell you what your connection can actually do right now, on this device, in this location. They do not tell you what your ISP promised you in your contract — that is a separate conversation. Speed tests are useful because they show you whether something is wrong with your connection, whether you are getting what you are paying for, or whether a particular activity (like video calls or online gaming) should work on your network.
The most widely used speed test is Speedtest by Ookla, which is free and works in a web browser. Other common options include Fast.com (run by Netflix), Google's built-in speed test (search "internet speed test"), and your ISP's own speed test tool if they provide one. All of them work the same way: they measure the same thing, so you should get similar results from any of them.
Key Takeaways
- Download speed is what matters most for everyday use like streaming and browsing; upload speed matters if you video call, stream, or upload files regularly.
- Run your speed test on a device connected by ethernet cable for the most accurate result, or on Wi-Fi if that is how you normally use the internet.
- Test at different times of day because your speed often drops during evening hours when your neighborhood is using more bandwidth.
- If your speed is much lower than what your ISP promised, restart your modem and router, then test again before contacting your ISP.
How to run a speed test on your device
Go to Speedtest.net in any web browser on the device you want to test. The page will detect your location and show a blue "Go" button. Click it. The test will run for about 30 to 60 seconds — it uploads a small file, downloads a small file, and measures the time. When it finishes, you will see your download speed, upload speed, and ping displayed on the screen.
For the most accurate result, connect your device directly to your modem with an ethernet cable instead of using Wi-Fi. If you cannot use ethernet, make sure you are close to your router and that no one else is using the internet heavily while you test. Close any browser tabs or programs that might be downloading or uploading in the background.
If you want to test your Wi-Fi specifically — to see whether the problem is your internet connection or your wireless router — run the test on Wi-Fi from the same room as your router, then run it again from another room. A big drop in speed means your Wi-Fi signal is weak in that location, not that your internet connection is slow.
Understanding your download and upload speeds
Download speed is what you use for almost everything: watching videos, loading web pages, downloading files, playing online games. Most people need 25 Mbps or higher for smooth streaming and browsing. If you have multiple people in your household streaming video at the same time, you may want 100 Mbps or higher.
Upload speed matters if you video call, stream to platforms like Twitch, or regularly upload large files. Most video calls work fine with 5 Mbps upload speed. If your upload speed is much lower than your download speed — say, 1 Mbps upload when you have 100 Mbps download — that is normal and expected. ISPs typically offer much more download than upload because most people download far more than they upload.
Compare your test results to what your ISP promised you in your contract or on their website. ISPs usually advertise speeds like "up to 100 Mbps" — the "up to" matters. You may not always hit that maximum, especially during peak hours. A result that is 80 to 90 percent of your advertised speed is generally acceptable. If you are getting 50 Mbps when you pay for 100 Mbps, something is wrong.
What ping means and why it matters for some activities
Ping is the time it takes for your device to send a signal to a server and receive a response, measured in milliseconds. For most internet use — browsing, email, streaming — ping does not matter much. A ping of 50 ms or 150 ms feels the same when you are watching a video.
Ping matters for online gaming and video calls. In online games, a high ping (above 100 ms) can cause noticeable lag, where your character moves after you press the button. For video calls, a ping above 150 ms can make conversations feel awkward because of the delay. Most home internet connections have a ping between 10 and 50 ms, which is fine for both gaming and calling.
If your ping is unusually high — say, 200 ms or more — it usually means your ISP's network is congested, or you are connecting to a server far away. Restarting your modem and router often fixes this. If it persists, contact your ISP.
Why your speed changes throughout the day
Your speed test result is a snapshot of this moment, not a may provide of consistent speed. Most home internet connections are slower during evening hours (roughly 6 p.m. to 10 p.m.) because more people in your neighborhood are using the internet at the same time. This is especially true if you have cable internet, which shares bandwidth with other households on your street.
To get a realistic picture of your connection, run speed tests at different times: early morning, midday, and evening. If your evening speeds are much lower than your daytime speeds, that is normal congestion. If your speed is consistently low at all times, the problem is likely your equipment, your plan, or something between your modem and your ISP's network.
Weather can also affect speed, particularly with satellite internet or fixed wireless connections. Heavy rain or snow can temporarily slow your connection. If you notice a pattern — always slow on rainy days, for example — that is a sign of a weather-related issue, not a problem with your service.
What to do if your speed is lower than expected
First, restart your modem and router. Unplug both devices, wait 30 seconds, plug in the modem first, wait for all its lights to stabilize (usually one to two minutes), then plug in the router. Wait another minute for the router to fully start up. Then run your speed test again. This fixes a surprising number of speed problems.
If the speed is still low, check whether other devices are using the internet. Streaming video, large downloads, or online games on other devices will reduce the speed available to your test. Ask everyone in your household to stop using the internet, then test again.
If your speed is still much lower than what you pay for, contact your ISP. Tell them your advertised speed, your actual speed (from your test result), and when the problem started. They may ask you to run a speed test on their own tool, which is fine — use it. If they cannot fix it, you have documentation that you are not getting what you paid for, which matters if you decide to switch providers or dispute a bill.
Choosing the right speed test tool
Speedtest by Ookla is the most common and widely recognized. It works on any device with a web browser and shows detailed results. Fast.com is simpler and faster — it gives you just the download speed in about 10 seconds, which is useful if you just want a quick check. Google's speed test (search "internet speed test" on Google) is built into Google Search and works the same way as Speedtest.
Your ISP may also offer their own speed test tool on their website or in their customer app. These are useful because they test your connection directly to your ISP's network, which can help diagnose whether a problem is on your ISP's side or on your home network. If you are troubleshooting a slow connection, run tests on both your ISP's tool and a third-party tool like Speedtest. If one is much slower than the other, that tells you where the problem is.
All of these tools are free. Do not pay for a speed test app or service — there is no reason to. Avoid apps that claim to "boost" your speed or "optimize" your connection; they do not work and may contain unwanted software.
Frequently Asked Questions
Should I test on Wi-Fi or ethernet?
Test on ethernet for the most accurate measurement of your internet connection itself. Test on Wi-Fi if you want to know how fast your wireless network actually is. If ethernet is much faster than Wi-Fi, your router may be too far away, too old, or in a location with interference. If they are similar, your Wi-Fi is working fine.
Why is my upload speed so much slower than my download speed?
This is normal. Most home internet plans are designed for downloading — streaming, browsing, gaming — so ISPs provide much more download capacity than upload. If you need faster upload for video calls or streaming, some fiber plans offer more balanced speeds, but they usually cost more.
Does a speed test use my data cap?
Yes, a speed test uses a small amount of data — usually 100 to 750 MB depending on the test. If you have a data cap on your internet plan, running multiple speed tests throughout the month will count toward that cap. One test per month is fine; testing daily could add up.
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. If you have multiple people streaming at once, add these numbers together. Two people streaming HD video at the same time need about 10 Mbps.
Can I improve my speed by changing my speed test settings?
No. The speed test measures what your connection actually does. You cannot change the result by choosing a different server or running the test at a different time — well, you can get different results at different times, but that is because your actual connection speed changed, not because the test changed.