Internet connection diagnostic
Bandwidth bottleneck test
Test whether download bandwidth, upload bandwidth, latency, jitter, or delay under load is limiting this browser session. The test transfers generated data between your browser and the BottleneckRadar server and usually uses no more than about 28 MB.
Live connection test
Download, upload, and latency
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Ready to test the route between this browser and BottleneckRadar.
Avoid running this test on a limited mobile data plan. Results can be influenced by this server, the route to it, Wi-Fi conditions, VPNs, and other active traffic.
What counts as a bandwidth bottleneck?
A bandwidth bottleneck occurs when the connection cannot move enough data for the workload. Low download speed can slow large files and streaming. Low upload speed can affect video calls, cloud backups, and live broadcasting. High latency or jitter can cause lag even when the Mbps result looks fast.
Why measure latency under load?
Some connections have healthy idle latency but become unresponsive during a download. The test sends small timing requests while download traffic is active and reports the increase. A large increase can indicate queueing or bufferbloat on the router or network path.
How to verify a weak result
- Pause downloads, backups, game updates, and video streams, then retest.
- Compare Wi-Fi with a wired Ethernet connection when possible.
- Disable a VPN temporarily and compare the route without it.
- Repeat the test at a different time to check for local or ISP congestion.