Bufferbloat Test
Does your connection lag when it’s busy?
Ready to test. See how much your latency rises when your connection is busy.
Provider
Test server
- About 35 seconds
- Up to 1 GB each way
- Pause other downloads first
What the numbers mean
- Bufferbloat
- Extra lag that shows up only when your connection is busy, like when someone is downloading a game or backing up photos. Your router is usually the cause, and it can often be fixed in its settings.
- Idle
- Your ping when nothing else is using the connection. This is the starting point.
- While downloading / uploading
- Your ping while the connection is working flat out. The closer this stays to idle, the better. Good: Less than 30 ms higher than idle.
- Grade
- How much your ping went up under load, from A+ (barely moved) to F (calls and games will struggle whenever someone else is using the internet). Good: A or A+.
How this test works
We check your ping for 5 seconds while things are quiet, then for 12 seconds while downloading at full speed, and 12 seconds while uploading. Your grade is based on how much the ping went up: A+ is under 5 ms, A under 30, B under 60, C under 200, D under 400, and F is anything more.
On very fast connections a browser can’t always max things out, so the result may look a little better than it really is.
Test traffic is handled by Cloudflare. Cloudflare privacy policy