What a Speed Test Measures
A speed test checks four things about your internet connection. Download speed is how
fast data reaches your device, and it shapes streaming, browsing, and file downloads.
Upload speed is how fast you send data out, which matters for video calls, cloud
backups, and posting large files. Latency (also called ping) is the round-trip time for
data between your device and a server, measured in milliseconds, and jitter is how much that delay varies from
moment to moment. Fast download and upload numbers make everything feel quick, while steady,
low latency and jitter keep video calls and games smooth. Unsure about a term? See the short
internet speed glossary.
What Is a Good Internet Speed?
A good internet speed depends on how many people and devices share the connection. These
figures are a practical starting point for most homes:
| Speed | Good for |
|---|
| 25 Mbps | HD and 4K streaming on one device. |
| 100 Mbps | A busy household, several devices at once. |
| 300 Mbps | Heavy 4K, gaming, and video calls together. |
| 1 Gbps | Large downloads and many heavy users. |
For a deeper breakdown by activity, see
what is a good internet speed, and compare
your result with the average internet speed in your country.
How to Read Your Speed Test Results
Download and upload are higher-is-better, and the table above says what yours should reach. The
other two numbers need a threshold rather than a target. Latency under about 30 ms feels
instant, 30 to 100 ms is fine for most things, and above 100 ms is noticeable in games and
calls. Jitter under 5 ms is excellent and under 20 ms is very good, while anything
sustained above 50 ms is what makes a call stutter even when the speed looks healthy.
The figure we report is the largest sample file that finished, not an average of the live
speed test graph, so a dip partway through does not drag
your number down. Test a few times at different hours, because busy evening networks are
slower than quiet mornings. On a phone, compare Wi-Fi with the
mobile data speed test over 4G or 5G to see which is
faster where you are. For the steadiest baseline, test on a wired connection with other
downloads paused.
Why SpeedOf.Me Is Accurate
SpeedOf.Me downloads and uploads real sample files in your browser, one at a time, each one
larger than the last, and stops at the size that gives a stable reading. That is the way a
single download or one video stream actually arrives, so the result reflects what one thing
on your connection will get rather than a best case assembled from many parallel
connections.
The sample files come from independent CDN edge servers, the same infrastructure that serves
the websites and video you use every day, and not from a server sitting inside your own
provider's network. That is the route your traffic really takes, and it is the main reason a
test measured against an in-network server reads higher than this one. We have measured this
way since 2011 and call the result Real-World Speed.
You do not have to take our word for it. SpeedOf.Me is named in California Public Utilities
Commission program rules as an accepted speed test for disputing broadband map coverage and
closing out state grants, it is recommended in the help pages of Disney+, Hulu and Nintendo,
and the method has been documented and analyzed in peer-reviewed networking research.
Textbooks set it as a classroom exercise too: see
who cites SpeedOf.Me, or the
lab version for teachers.
Speed Test FAQ
Why is my speed lower than my plan?
Providers advertise a maximum, but real speed drops with Wi-Fi range, older routers, network
congestion, and the number of devices sharing the line. Testing wired, close to the router,
shows the speed your line actually delivers.
Why do results differ between speed tests?
Different tests use different servers, different numbers of parallel connections, and
different ways of averaging, so two run a minute apart can disagree widely and both be
right. What matters is comparing like with like: pick one test and watch it over time
rather than hunting for the highest number.
What is the difference between Mbps and MBps?
Mbps means megabits per second and measures connection speed, while MBps means megabytes per
second and measures file size. There are 8 bits in a byte, so a 100 Mbps connection downloads
about 12.5 megabytes per second.
How do I test my Wi-Fi speed?
Run the test where the Wi-Fi feels slow, then again beside the router, then over a cable if
you can. The gaps say which layer is at fault: a big jump next to the router points at
coverage, a low reading everywhere on Wi-Fi points at the router or a crowded 2.4 GHz band,
and a low wired reading points at the broadband line itself. Moving to the 5 GHz band, where
your router offers one, usually helps in the same room.
How much data does a speed test use?
It adapts to your connection, so a slow line may move only a few megabytes while a gigabit
line can use a couple of hundred. Worth knowing before running it repeatedly on a capped
mobile plan.
More answers on the
internet speed test FAQ, or start with
how to test your internet speed.
