What you're actually measuring when you test your speed

An internet speed test measures three things: download speed (how fast data comes to your device), upload speed (how fast data leaves your device), and ping (how long it takes for your device to communicate with a server). Download speed is what most people care about — it determines whether Netflix buffers or loads instantly. Upload speed matters if you video call, stream games, or send large files. Ping measures delay, and high ping makes online games feel sluggish.

Speed tests work by sending a file from a test server to your device, measuring how long it takes, then sending a file back. The result is in megabits per second, or Mbps. One megabit is one million bits — not to be confused with megabytes, which are eight times larger. Your internet bill probably lists a speed like "100 Mbps" or "1 Gbps" (gigabits, or 1,000 Mbps). A real-world speed test usually shows something lower than your plan promises, and that's normal.

Key Takeaways

  • Speedtest.net and Fast.com are the two most widely used free speed tests and give similar results in most homes.
  • Run your test on a device connected by ethernet cable for the most accurate result, or on WiFi if that's how you actually use the internet.
  • Close other apps and browser tabs before testing, because downloads and video streaming will artificially lower your numbers.
  • Test at different times of day — speeds often drop during evening hours when your neighborhood's network is busier.
  • Write down your results so you can compare them over weeks or months and spot patterns in slowdowns.

Running a speed test on your computer or phone

Speedtest.net (owned by Ookla) is the most common choice. Go to speedtest.net in any web browser, click the large "Go" button, and wait 30 to 60 seconds. The test will show your download speed, upload speed, and ping. You don't need to create an account, though Ookla will store your result unless you delete it manually. The test works on phones, tablets, and computers.

Fast.com (run by Netflix) is simpler and faster. Go to fast.com and it starts testing immediately — no button to click. It shows download speed prominently and upload speed in a smaller line below. Fast.com doesn't ask for any information and doesn't store results tied to your identity.

Both tests are free and give results within a few seconds of each other in most homes. Pick whichever interface you prefer. If one seems unusually slow, run the other as a check — a big difference might mean a temporary network hiccup rather than a real problem.

Getting an accurate result: ethernet vs. WiFi

An ethernet cable (the physical wire that plugs into your router and computer) will always show faster speeds than WiFi from the same router, because WiFi has more interference and distance limitations. If you're testing to see whether your internet plan is delivering what you're paying for, use ethernet. Plug one end into your router and the other into your computer, then run the test.

If you can't use ethernet, or if you want to know your real-world WiFi speed, test on WiFi instead — but test from the same room as your router. WiFi speed drops sharply as you move away, so testing from your bedroom when the router is in the living room will show artificially low numbers. For a fair WiFi test, sit within 15 feet of the router with a clear line of sight.

Phone users are almost always on WiFi, so test your phone from wherever you normally use it. That number is more useful than an ethernet result, because it reflects your actual experience.

Why your speed test might show lower numbers than your plan

Internet service providers advertise speeds like "100 Mbps" as a maximum under ideal conditions, not a may provide. Real-world speeds are usually 10 to 20 percent lower because of network overhead, distance from the provider's equipment, and the number of people using your connection at the same time. If your plan is 100 Mbps and you consistently see 80 to 90 Mbps, that's normal and working as intended.

If you see significantly less — say, 30 Mbps on a 100 Mbps plan — something is wrong. Before calling your provider, close all other apps and browser tabs, disconnect other devices from WiFi, and test again. Streaming video, downloads, or video calls in the background will tank your speed test results. If the speed is still low after closing everything, restart your router by unplugging it for 30 seconds, plugging it back in, and waiting two minutes for it to fully boot.

Testing at different times to spot patterns

Internet speeds often drop during evening hours (roughly 7 p.m. to 11 p.m.) when many people in your neighborhood are streaming video or gaming. This is normal congestion, not a problem with your connection. To understand your own pattern, run a speed test at the same time each day for a week and write down the results. If speeds are consistently fast in the morning and slow at night, congestion is the cause.

If speeds are slow all day and all night, or if they suddenly dropped and stayed low, that suggests a problem with your connection or equipment. In that case, the speed test result is useful information to give your internet provider when you contact them — they can see whether the problem is on their end or yours.

Understanding ping and why it matters for gaming

Ping is measured in milliseconds (ms) and shows how long it takes your device to send a signal to a test server and get a response back. Most speed tests show this number, though it's usually small and easy to miss. For regular web browsing and video streaming, ping doesn't matter much — anything under 100 ms is fine. For online gaming, a lower ping is noticeably better. A ping under 50 ms feels responsive; over 100 ms starts to feel sluggish.

Ping is determined by your distance from the server and the quality of your connection, not by your download speed. You can have fast download speeds and high ping, or slow download speeds and low ping. If you game online and notice lag, check your ping during a speed test. If it's consistently over 100 ms, contact your internet provider — they may be able to route your connection through a different path, or the problem might be on your end (a WiFi connection instead of ethernet, for example).

Frequently Asked Questions

Why does my speed test show different numbers each time I run it?

Small variations are normal — network traffic changes second to second. If you see a 10 to 15 Mbps difference between tests, that's expected. Larger swings (50+ Mbps difference) suggest something else is using your connection. Close all apps and tabs, then test again. If the number is still jumping around, restart your router.

Can I test my speed on my phone while connected to mobile data instead of WiFi?

Yes, but the result measures your mobile carrier's speed, not your home internet. Mobile speeds vary based on how many people are on the network and how far you are from the cell tower. If you want to test your home internet, connect to your WiFi first.

What's a good internet speed?

It depends on what you do. For email and web browsing, 10 Mbps is plenty. For streaming one video in HD, you need about 5 Mbps. For video calls, 2.5 Mbps upload speed matters. If four people in your home are streaming video at the same time, you need 20+ Mbps. Your plan should be faster than your peak need.

Should I test my speed using WiFi or ethernet?

If you want to know what your internet plan is actually delivering, use ethernet. If you want to know your real-world speed on the device you actually use, test on WiFi from where you normally sit. Both numbers are useful for different reasons.

My speed test shows I'm getting less than half my plan speed. What should I do?

First, close all other apps and tabs, disconnect other devices, and test again. If the speed is still low, restart your router. If it's still low after that, write down the speed test result and call your internet provider with that number — it helps them diagnose the problem faster than describing it in words.