Internet Speed Checker
Test your download, upload and latency, and how the connection copes when it's busy
- Download and upload speed
- Latency and jitter
- Latency under load
About Internet Speed Checker
Runs a speed test against Cloudflare's nearest server and reports download and upload speed, latency, jitter, and how far latency climbs while the line is busy (bufferbloat). The results are turned into plain answers, such as whether video calls or 4K streaming should work. On a slow connection the test stops after a minute and reports what it managed to measure.
What each number means
- Download and upload: how much data the connection moved per second, in megabits (Mbps)
- Latency (ping): how long a small request takes to get to the test server and back
- Jitter: how much latency varies from one request to the next; lower is steadier
- Latency under load: how much latency rises while the connection is busy downloading or uploading, also called bufferbloat
Why latency under load matters
Many connections test fast but feel slow because latency jumps when someone else starts a download or a backup. Video calls freeze and games lag even though the headline speed looks fine. If latency under load is high, turning on Smart Queue Management (SQM) or QoS in your router usually helps more than a faster plan.
Getting a fair result
The test measures from this browser to Cloudflare’s nearest server, so Wi-Fi signal, other devices, VPNs and browser extensions all affect it. For the most representative number, pause large downloads, use a wired connection if you can, and run the test more than once. On slow connections the test stops after a minute and reports what it measured so far.
Further reading
Questions people ask
- Why is my result lower than my plan’s speed?
- Plans usually advertise a maximum. Wi-Fi, other devices on the network, the distance to the test server and busy times of day all reduce what one browser measures.
- Why isn’t packet loss shown?
- Packet loss needs a special relay connection that many networks and browsers block. When it can’t be measured, the result says so instead of showing zero.
- Does the test use a lot of data?
- It downloads and uploads progressively larger files until each transfer takes about a second, or until a minute has passed. On a very fast connection a full test can use more than 1 GB, so avoid running it repeatedly on a metered plan.