Bufferbloat Test
Speed tests measure how fast your line is when nothing else is happening. This test measures what happens to your latency when your connection is actually busy. That is the thing that ruins games and video calls.
The test takes about 35 seconds and transfers data at your full line speed (roughly 1-4 GB on fast connections). Avoid running it on a metered connection.
Your Bufferbloat Grade
| Baseline (idle) | Download loaded | Upload loaded | |
|---|---|---|---|
| Median latency | — | — | — |
| Latency increase | — | — | — |
| 95th percentile | — | — | — |
| Grade | — | — | — |
| RPM | — | — | — |
| Throughput | — | — | — |
Probe loss under load: — · Probe type: —
RPM (round-trips per minute under load) is the responsiveness metric used by Apple and the IETF. Above 1,000 is excellent. Below 300 feels sluggish under load.
What your result means in practice
About Bufferbloat
Bufferbloat is latency caused by oversized buffers in your router or modem. When your connection gets saturated by a big upload, a cloud backup, or someone streaming, packets pile up in those buffers instead of being dropped promptly. Nothing is technically lost, but everything arrives late. Your idle ping of 20ms can jump to 300ms or more, and real-time apps fall apart.
This test measures your latency three ways: at rest, while your download is fully saturated, and while your upload is fully saturated. The difference between idle and loaded latency is your bufferbloat. We grade it on the same A+ to F scale popularized by DSLReports, so you can compare results with other tools directly.
Most bufferbloat tests probe latency with HTTP requests that share connections with the load traffic, so they sometimes measure browser congestion instead of your router's queue. That is a known weakness, and it shows up most on mobile. Our probe runs over a WebRTC unreliable data channel instead, a separate UDP flow to a dedicated test server, so the number you see reflects what your router is actually doing.
How to fix bufferbloat
- Enable Smart Queue Management (SQM). Modern queue algorithms (fq_codel, CAKE) keep buffers short by design. Look for SQM, "QoS", or gaming/conferencing optimization settings in your router. On eero, enable "Optimize for Conferencing and Gaming" in Labs.
- Update or replace old equipment. Routers and modems from before ~2018 rarely have modern queue management. If your grade is D or F and your router has no SQM option, the router is usually the fix.
- Re-test after every change. Toggle a setting, run this test again, compare grades. SQM done right typically turns an F into an A.
Also check your connection for packet loss
Run Packet Loss Test