FIXED: Cloudflare speed test is inaccurate

I’ve just finished testing my speed at The results indicate I have >20mbps uplink speed. But, I’m on a Telstra velocity plan here in Australia and my plan indicates I’m locked to 5mbps uplink speed. I verified this by running iperf in server mode on a remote server and then running iperf in client mode on my laptop. The results indicate 5mbps.

How is it that Cloudflare is showing me >20mbps uplink speed?

That’s an actual upload speed test that shows how much data the browser was able to push to CF’s server, so something might be wrong in your host’s throttling configuration or a number of other things might not be adding up. Do you get similar results at,, and

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How far away was this remote server? What is your latency to it?

Hi Judge.

Yes, they are all similar to my iperf test.

The Google test though did not finish - it froze on that screen (bottom right of collage below):

That’s interesting, i’m also with Telstra but on a 50/20 connection, and these are my results

Judging by the graph on your upload, the speedtest is probably using your results for the 100kB upload test, because it takes the 90th percentile. The inaccuracy in the 100kB upload measurement is probably why it is over-reporting your upload speed, either that or Telstra isn’t throttling uploads below a certain threshold in size

That could be it. My iperf test starts out high then settles down to the actual speed I’m limited to. The Cloudflare result initially gave me hope that maybe Telstra had given pity to us not on NBN and decided to up our uplink speed - only to be slamed back to earth by iperf - :frowning:.

Maybe Cloudflare needs to tweak their uplink calculator to throw away the peak speed as it is definitely an outlier:

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100kb is a good file size for testing things like website speed because it’s a realistic number (100kb of HTML and some 100kb images) but it seems like the worst way to test sustained upload speed from a home connection.

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