How to use it
- 1.Close other downloads, streams and video calls, and connect by cable if you want to know what your line can do.
- 2.Click “Start test”. Latency is measured first, then download and upload speed; the numbers update as the test runs.
- 3.Read the results: download and upload in megabits per second (Mbps), latency and jitter in milliseconds (ms).
- 4.Check the ratings for streaming, gaming and video calls, and click “Test again” to compare after changing something.
What the numbers mean
Download speed is how fast data reaches you: web pages, videos, updates. Upload speed is how fast you can send data: video calls, backups, sending large files. Both are measured in megabits per second (Mbps); divide by 8 to get megabytes per second, so 100 Mbps downloads a 1 GB file in about 80 seconds.
Latency (often called ping) is the time a small request takes to travel to the server and back. Under 20 ms feels instant, under 50 ms is fine for almost everything, and above 100 ms makes games and calls feel sluggish. Jitter is how much latency varies from one request to the next; high jitter causes choppy audio and video even on a fast line.
The test also measures latency while the line is busy downloading and uploading. If it jumps far above the idle value, your router is queuing too much data (bufferbloat), and calls and games suffer whenever someone else in the house downloads something.
How much speed you need
For HD video 5 to 10 Mbps is enough, and 4K streaming needs about 25 Mbps per stream. A video call uses 2 to 4 Mbps in each direction, so upload speed matters as much as download. Online games need little bandwidth but low, stable latency.
Add up what your household does at the same time: two 4K streams, a video call and a game download need far more than any single one of them. If the ratings show “Poor” for something you do often, the connection is the bottleneck.
Why results differ between tests
Wi-Fi is the most common reason for a slow result: walls, distance and neighbouring networks can halve the speed. Test again next to the router or over a cable to see what the line itself delivers. Other devices using the connection, VPNs and browser extensions also lower the numbers.
Every speed test measures to a particular server. This one uses the nearest of Cloudflare’s data centres, which are in more than 300 cities, so it reflects how fast you can reach the modern web. A test against your provider’s own server can show higher numbers than you’ll see anywhere else.
Questions and answers
Why is my speed lower than my plan promises?
Plans advertise the maximum speed of the line, and Wi-Fi, other devices on the network and busy evening hours all take a share. Test over a cable with nothing else running; if the result is still far below the plan, contact your provider with the numbers.
What is a good internet speed?
For one person, 25 to 50 Mbps download and 5 to 10 Mbps upload covers streaming, calls and browsing comfortably. A household that streams in 4K, works from home and games at the same time is better off with 100 Mbps or more. Latency below 50 ms matters more than raw speed for calls and games.
What’s the difference between Mbps and MB/s?
Internet speeds are measured in megabits per second (Mbps), file sizes in megabytes (MB). One byte is eight bits, so 100 Mbps moves about 12.5 megabytes every second.
Does the speed test use my data allowance?
Yes. The test transfers real data to measure accurately, and it keeps increasing the file size until the measurement is reliable. On a slow connection that’s a few megabytes, on a gigabit line it can be several hundred megabytes, so be careful on a limited mobile plan.
Is the test private?
The measurement runs between your browser and Cloudflare’s network, so Cloudflare sees your IP address, as with any website it serves. nestoo doesn’t receive or store your results, and the tool doesn’t send them to Cloudflare’s statistics either.