If you typed "where to" into a search box, the fastest answer is FAST.com, it loads instantly, needs no account, no card, and works in any browser on any device, anywhere. For a more detailed readout with server choice and history, use Speedtest by Ookla, which is also free and runs in your browser or as an app on iOS, Android, macOS, Windows, and Apple TV.
Why Two Speed Tests Disagree
You ran a test, got 200 Mbps, ran another, got 80 Mbps, and now you think one of them is lying. They are not. The number changes because the test is not measuring "your internet" as a fixed thing, it is measuring a specific path between your device and a specific server at a specific moment. Speedtest by Ookla lets you pick the server, and its own help pages say results differ if you test different connections or different servers. FAST.com, by default, connects you to a server near the Netflix content delivery network, which may be closer or farther than the one your ISP prefers.
The other big variable is your own network. If you are on Wi‑Fi, walls, distance, and interference from neighbors all eat speed. If you have a VPN on, that adds encryption overhead and routes your traffic through another country. If someone else in the house is streaming, downloading, or backing up to the cloud, that steals bandwidth. The test you ran five minutes ago is already stale because the conditions changed.
Before you blame your ISP, do this: plug your computer directly into the modem or router with an ethernet cable. Turn off the VPN. Close every app that uses the network, streaming, downloads, cloud sync, even a phone on Wi‑Fi that is backing up photos. Then run the test again. If it is still slow, reboot the modem and router by unplugging them for 30 seconds, plugging them back in, waiting two minutes, and testing again. AT&T’s speed test help page says exactly this: disconnect other devices, close apps, and test on the device you want to measure. Verizon’s speed test adds the same advice: use ethernet, no VPN, no streaming apps during the test.
Which Number Actually Matters
Speed tests give you three numbers: download, upload, and ping (also called latency). For almost everything you do, loading web pages, streaming video, scrolling social media, download speed is the number that matters. That is the speed at which data comes to you, and it is what your ISP advertises as "up to 300 Mbps." CenturyLink’s help page explains that the test measures ping first, then download and upload packets, and the download figure is what most people mean by "how fast is my internet."
Upload speed matters when you send data: video calls, posting photos, cloud backup, live streaming, sending large files. If you work from home and join video meetings, or if you stream games, upload is not optional, it is the difference between a clear call and a frozen one. Speedcheck notes that browser tests are fine on computers, but for accurate mobile results you should use their app, because the browser on a phone may not use the full radio.
Ping (or latency) is the time in milliseconds for a data packet to travel to the server and back. Low ping, under 30 ms is great, under 100 ms is fine for most things, matters for gaming, video calls, and any interactive app where you notice delay. Spain’s CNMC official speed test measures fixed, Wi‑Fi, fiber, and 4G/5G mobile connections, and it reports all three numbers, but if you are not gaming or on a call, ping is the one you can ignore.
The Free, Legal, No-Account Options
Here is the list of tests that cost nothing, require no sign-up, and do not ask for a card. All of them are free because they are either paid for by the company running them or by a regulator.
- FAST.com, This is Netflix’s test. It is a single page, no buttons, no ads, no account. It works globally on any device with a browser. It is free because Netflix pays for it as a service to show you how fast your connection is to their servers, which is exactly what you want to know if you are about to stream. It only shows download speed by default, but click "Show more info" to see upload and latency.
- Speedtest by Ookla, The most detailed free option. You get a server picker (so you can test against a server in your city, not one across the country), a history of past results, and apps for every platform. No account is needed for the basic test, and no card is ever requested. It is free because the service itself is the product, it shows you ads and offers premium features, but the core test is free forever.
- CNMC official speed test, This is Spain’s government regulator. It is free, ad-free, and official. It works in Spain and measures fixed, Wi‑Fi, fiber, and 4G/5G mobile. No account, no card, no catch, it exists because the regulator wants consumers to have a trustworthy tool to check what their ISP is actually delivering.
- AT&T speed test, Free, no account, no card. It uses AT&T’s own servers, so it is a good test of your connection to AT&T’s network specifically. It is tied to AT&T’s service footprint, so if you are not an AT&T customer, it may still work, but the result is only meaningful if you are on their network.
- Verizon speed test, Same deal as AT&T: free, no account, no card, and it tests from Verizon’s servers to your device. It is a good choice if you are a Verizon customer, but for everyone else, it is not the best measure of general internet speed.
- CenturyLink speed test, Another operator tool, free and account-free. It picks the closest server, measures ping first, then download and upload. It is fine if you are a CenturyLink customer, but for a general test, the others are better.
What to Check Before You Commit to One Test
Do not just run one test and call it a day. Run two different tests, say, FAST.com and Speedtest, and if they disagree, that is normal. What you are looking for is consistency. If FAST.com says 200 Mbps and Speedtest says 180 Mbps, your connection is fine. If FAST.com says 200 Mbps and Speedtest says 20 Mbps, then the problem is likely the server you picked on Speedtest, or your path to that server is congested. Try a different server on Speedtest and see if the number changes.
Also, check the time of day. Evenings are peak hours when everyone is streaming, so a 7 PM test will be slower than a 7 AM test. If you want a fair comparison, test at the same time of day over several days. And if you are testing on a phone, hold it next to the router, not in the bathroom, because Wi‑Fi signal strength changes everything.
One more thing: if your test is slow, do not immediately blame the internet. Check Downdetector to see if your ISP is having an outage in your area, or use Whatsmyip.now to see your public IP address and whether you are using a VPN or proxy. That site is free, needs no account, and shows live outage reports. If your ISP is down, no speed test will help until it is back.
Frequently Asked Questions
Why is my download speed slower than what I pay for?
Because "up to" is doing a lot of work. Your plan advertises the maximum speed under ideal conditions, not the speed you get at 8 PM on a Tuesday. Wi‑Fi, distance from the router, other devices on your network, and the server you are testing against all lower the number. Run the test over ethernet with everything else off, and if it is still far below your plan, call your ISP.
Should I use a mobile app or a browser for the test?
For a phone, the app is usually more accurate because it can use the full radio and does not have browser limitations. Speedcheck says mobile apps are recommended for accurate results on phones. On a computer, a browser test is fine, just make sure you are not running other apps in the background.
What is a good ping for gaming?
Under 30 ms is excellent, under 60 ms is good, and under 100 ms is playable for most games. If your ping is above 100 ms, you will notice lag. Ping is more about the distance to the server and the quality of your connection than your download speed, so a fast connection can still have bad ping if the server is far away.
Can I test my speed without a computer?
Yes. FAST.com works in any browser on a phone or tablet. Speedtest has apps for iOS and Android. The CNMC test works on mobile too. Just remember that a phone on Wi‑Fi will give different results than a phone on cellular data, so test the connection you actually care about.
Why does my speed test say 100 Mbps but my files download at 10 MB/s?
Because internet speed is measured in megabits per second (Mbps), and file size is measured in megabytes (MB). There are 8 bits in a byte, so 100 Mbps is about 12.5 MB/s. That is normal. If you see a file downloading at 10 MB/s, you are getting roughly 80 Mbps, which is about right for a 100 Mbps connection.
More on internet tools
This is one of the guides in Free Online Tools for Checking Your Internet Connection. The others:
