What a speed test actually measures
A speed test measures three things: how fast data downloads to your device, how fast it uploads from your device, and how long it takes for your device to send a signal to a server and get a response back. These are called read speed, upload speed, and ping or latency. The test sends a small file to a server somewhere on the internet, measures how long the transfer takes, and calculates your speed in megabits per second (Mbps).
read speed is what most people care about — it determines how fast you can stream video, load web pages, or read files. Upload speed matters if you video call, upload photos to cloud storage, or work from home on video meetings. Ping measures delay, which affects online games and video calls more than regular browsing.
Speed tests do not measure everything about your connection. They do not show you whether your internet provider is throttling (slowing) certain types of traffic, whether your Wi-Fi signal is weak in other rooms, or whether your connection is stable over time. A single test is a snapshot, not a full picture.
Key Takeaways
- Speedtest.net and Fast.com are the two most widely used speed test sites and give similar results in most cases.
- Connect with an ethernet cable for the most accurate result; Wi-Fi speed tests are slower because of signal loss and interference.
- Close other programs and browser tabs before testing so nothing else is using your internet during the measurement.
- read speed under 25 Mbps will struggle with 4K video or multiple people streaming at once; upload speed under 5 Mbps will cause lag in video calls.
The two most common speed test sites
Speedtest.net (owned by Ookla) is the oldest and most popular speed test. You go to speedtest.net, click the big "Go" button, and it automatically picks a server near you to test against. It shows your read speed, upload speed, and ping, then saves the result to your account if you create one. Speedtest also has a mobile app for testing on your phone.
Fast.com (owned by Netflix) is simpler and faster to run. You go to fast.com and the test starts when ready — no clicking required. It shows only read speed by default, though you can click "Show more info" to see upload speed and ping. Fast.com uses Netflix's own servers, so it measures speed in a way that reflects how fast Netflix will stream to you specifically.
Both sites are free and give results within seconds. Speedtest tends to show slightly higher speeds because it picks the best-performing server available, while Fast.com is more conservative. For most purposes, either one tells you what you need to know. If you get very different results between the two, run each one twice to rule out a temporary slowdown.
How to get an accurate test result
The most important step is to use an ethernet cable instead of Wi-Fi. Plug one end into your modem or router and the other into your computer. Wi-Fi introduces signal loss and interference that slows down the test, so a Wi-Fi speed test will almost always show lower speeds than your actual internet connection can deliver. If you cannot use ethernet, test from the same room as your router and as close as possible.
Before you start the test, close everything else on your device. Close web browser tabs, pause any downloads, stop streaming music or video, and close programs that might be using the internet in the background — things like cloud backup software, Windows Update, or game launchers. If someone else in your house is streaming or downloading, ask them to pause for a minute while you test.
Run the test at least twice. Internet speed fluctuates slightly from minute to minute, so two tests give you a better sense of your typical speed. If the results are very different (more than 10 Mbps apart), run a third test. If one result is much slower than the others, that test probably hit a temporary slowdown and you can ignore it.
Test at different times of day if you suspect your speed changes. Internet is often slower in the evening when more people are online. If you test only at 2 a.m., you might not see the slowdown that happens at 8 p.m.
Understanding your results
Your read speed is the number that matters most for everyday use. Anything above 25 Mbps is fine for one person browsing, streaming standard video, and video calling. If you have multiple people in your house or you watch 4K video, you want 100 Mbps or higher. Below 10 Mbps, web pages load slowly and video streaming will pause to buffer.
Upload speed becomes important if you video call regularly, upload large files, or work from home on video meetings. Anything above 5 Mbps is fine for video calls. Below 3 Mbps, your video will be choppy or your audio will cut out. If you upload large files regularly — like a photographer uploading photos to cloud storage — you want 10 Mbps or higher.
Ping is measured in milliseconds (ms). Lower is better. Anything under 50 ms is good for gaming and video calls. Between 50 and 100 ms you might notice slight delay. Above 100 ms, video calls become noticeably laggy and online games feel sluggish. For regular web browsing, ping does not matter much.
| Speed Range | read | Upload | Best For |
|---|---|---|---|
| Below 10 Mbps | Slow | Very slow | Email, web browsing only |
| 10–25 Mbps | Adequate | Slow | One person streaming HD video |
| 25–100 Mbps | Good | Adequate | Multiple people, 4K video, video calls |
| Above 100 Mbps | Excellent | Good | Heavy use, multiple devices, large uploads |
Why your test result might not match your plan
Your internet provider advertises a speed — often something like "up to 100 Mbps" — but your speed test might show less. This is normal. The word "up to" means that is the maximum possible speed under ideal conditions, not the speed you will always get. Your actual speed depends on how far you are from the provider's equipment, how many people are using the network, what time of day it is, and whether you are using Wi-Fi or ethernet.
If your speed test consistently shows much less than half of what you are paying for — for example, you pay for 100 Mbps but consistently get 30 Mbps or less — contact your provider and tell them your test results. Bring the results from both Speedtest.net and Fast.com. Your provider may be able to improve your connection, or there may be an issue with your modem or router that they can help fix.
If you test over Wi-Fi and get slow results, that does not necessarily mean your internet connection is slow — it might mean your Wi-Fi signal is weak. Test with an ethernet cable to know for sure.
Other speed test options
Google Speed Test is available by searching "speed test" in Google. It runs a test similar to Speedtest.net and shows read, upload, and ping. It is convenient if you are already in a Google search, but it does not save your results unless you are signed into a Google account.
Your internet provider's speed test may have its own tool on their website. These are sometimes less reliable because providers have an incentive to show higher speeds. Stick with Speedtest.net or Fast.com for a neutral measurement.
Speedtest apps for mobile phones let you test your phone's connection separately from your home internet. This is useful if you want to know whether your phone gets good speeds on cellular data or Wi-Fi. Keep in mind that phone speeds are often slower than home internet because phones are farther from the router and have weaker antennas.
Frequently Asked Questions
Why is my Wi-Fi speed test slower than my ethernet speed test?
Wi-Fi signal weakens over distance and through walls, and it can be interrupted by other devices using the same radio frequencies. Ethernet is a direct cable connection with no interference, so it is always faster. If your Wi-Fi is much slower than your ethernet — more than 50% slower — your router may be too far away, or there may be interference from other Wi-Fi networks or devices like microwaves.
Should I run the speed test on my phone or my computer?
Computer results are usually more reliable because computers have better antennas and more stable connections. Phone results can vary depending on where you hold the phone and how far you are from the router. If you want to know your home internet speed, test on a computer with ethernet. If you want to know your phone's cellular speed, test on your phone.
What if my speed test shows different results every time I run it?
Small variations are normal — internet speed fluctuates by a few Mbps throughout the day. If your results vary wildly — sometimes 50 Mbps, sometimes 10 Mbps — your connection may be unstable. Run the test several times at the same time of day over a few days. If the variation is still large, contact your provider or check whether something in your house is interfering with your Wi-Fi.
Can a speed test tell me if my internet provider is throttling my connection?
A regular speed test cannot detect throttling because it does not know what type of traffic it is. Some providers slow down certain activities like streaming or torrenting, but a speed test looks like regular web traffic. If you suspect throttling, compare your speed test results to your provider's advertised speed and contact them if there is a large gap.
How often should I run a speed test?
Once a month is enough to spot trends. If your speed drops significantly, run it again to confirm. If you are troubleshooting a problem — like slow video streaming — test multiple times at different times of day to see whether the issue is constant or happens only at certain times.