Free Tool

Bufferbloat Test

Measure how your router handles network congestion. High bufferbloat causes lag spikes during downloads.

What Is Bufferbloat

Bufferbloat happens when your router's buffers are too large. When you start a download, the buffers fill up and add massive latency. Your ping jumps from 20ms to 500ms. The connection becomes unusable for gaming or video calls. Bufferbloat affects most consumer routers.

Testing for Bufferbloat

Run a speed test while monitoring your ping. If your ping spikes when the download starts, you have bufferbloat. The difference between idle ping and loaded ping is your bufferbloat score. Under 50ms is good. 50-100ms is moderate. Over 100ms is bad and needs fixing.

Fixing Bufferbloat

Enable Smart Queue Management (SQM) or QoS on your router. Set bandwidth limits to 90% of your plan. Upgrade to a router with good SQM support like those running OpenWrt or IQrouter. Reduce buffer sizes if your router allows it. Use our DNS speed test to check if DNS adds delay.