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Speed Test

Measures download, upload, idle and loaded latency, jitter, and bufferbloat. Tests connect to the nearest Cloudflare PoP using the same endpoints as speed.cloudflare.com, so results reflect real-world throughput, not a lab benchmark.

Ready
↓ Download
—Mbps
↑ Upload
—Mbps
⟳ Idle Ping
—ms
📶 Bufferbloat
—
Latency increase under load

About this test

The test runs four phases against Cloudflare's globally-distributed speed-test endpoints:

  1. Idle latency — 10 small HEAD/GET requests. Reports median and jitter (variance between probes).
  2. Download — parallel chunked downloads, measured in real time after a 1.5s ramp-up. Final number is the sustained throughput, not a peak.
  3. Upload — multi-MB POST with progress-tracked throughput. Same warm-up window applied.
  4. Bufferbloat — pings the server while a heavy download is running. Subtracts idle latency to isolate the queue delay from your own router or modem. A <30ms · B <60ms · C <100ms · D <200ms · F 200+ms

If your bufferbloat grade is poor (C or worse) but your download/upload look fine, that's usually fixable: enable SQM or fq_codel on your router, or upgrade to a router that supports them. Bufferbloat is what makes a 1Gbps connection feel laggy on a video call when someone else is downloading.

Total runtime is about 15–20 seconds. Data transferred scales with your connection speed: a 100 Mbps line moves ~75 MB during the test, a 1 Gbps line ~750 MB. Save it for Wi-Fi if you're on a metered plan.

Frequently Asked Questions

What is bufferbloat and why does it matter?
Bufferbloat is latency that spikes under load when oversized buffers queue packets. It is why video calls stutter during an upload. This test compares idle versus loaded latency and grades the difference.
Why is my speed lower than my plan rating?
Browser tests are limited by Wi-Fi, device, congestion, and the path to the server. A wired connection, off-peak, with nothing else running gives the most accurate read.
What is a good bufferbloat grade?
An A means latency barely rises under load. B or worse suggests your router would benefit from Smart Queue Management (SQM / fq_codel) to keep latency low while the link is saturated.