Internet diagnostic tool

Bufferbloat test

Bufferbloat happens when routers or modems queue too much traffic under load. Your speed can look fine, but calls and games lag whenever someone uploads, streams, or downloads. This test measures it: your latency at rest versus while the line is full.

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Run a quick browser-based diagnostic for calls, gaming, streaming, VPN, and remote work. Verdicts appear before raw technical numbers.

Measured from your browser to the nearest Cloudflare server with Cloudflare’s open-source speed test engine, so results reflect your connection to Cloudflare, not every site you use. Uses roughly 20–190 MB of data, more on faster connections, so use Wi-Fi if you are on a metered plan. Results are not sent back to Cloudflare. How we measure

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Ping jumping when someone else streams or uploads? Read why your ping rises when the line is busy and how to fix it.

Bufferbloat test: what the results mean

Signs of bufferbloat

Ping spikes during uploads.
Zoom gets choppy when backups run.
Games lag while someone streams or downloads.
VPN or remote desktop feels delayed under load.

Best fixes

Enable Smart Queue Management if your router supports it.
Limit upload-heavy apps.
Upgrade old routers.
Test again while the network is busy.

Frequently asked questions

What is bufferbloat?

Bufferbloat is excessive queueing in network equipment that causes latency spikes when the connection is busy.

How does this bufferbloat test work?

It measures your idle latency, then keeps measuring latency while it downloads and uploads at full speed. The increase is your bufferbloat, graded from A+ (under 5 ms) to F (over 400 ms).

How do I fix bufferbloat?

Enable SQM/QoS on a capable router, reduce upload saturation, use Ethernet, or upgrade router firmware/hardware.

Can fast internet have bufferbloat?

Yes. Even fast plans can lag under load if the router queues traffic poorly.

Recommended next steps

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