A page weight reference for the web – the 1 MB website

“Every line is the perfect length if you don’t measure it.”
— Marty Rubin

In engineering disciplines it’s very important to have fixed frames of reference to enable easy comparison of results. In the web developer community we already have many page weight measuring tools such as our own mobiReady and WebPagetest.org.

So we have the weighing scales but who ensures that they are working as expected? In looking through the various tools out there page weight results varied widely enough to cause serious concern. In a recent test we carried out there was almost no consensus and some of the discrepancies were quite alarming. What is the web page weight equivalent of the international prototype kilogram (IPK)?

Given that there isn’t any existing reference site we decided to make one. http://1mb.website is a web page whose transfer weight is precisely 1 MB, or 1,000,000 bytes. You can read more about the technical details on the page itself.



The site thus becomes a very useful reference for anyone running web page weight tests. If your test tool reports a transfer weight of anything other than 1.0 MB for this page, something is up.

It’s also a useful tool for testing other things on the web e.g. if anything is meddling with your web content en route. If the transfer size is not correct there are grounds for suspicion. As an example, in testing this page internally we noticed that some versions of Chrome on Windows were reporting a transfer weight of 1.1 MB where Linux and OS X versions correctly reported 1.0 MB. After some sleuthing it turns out that the ESET anti-virus application was proxying web requests and altering the content on the fly.

Another use case for a fixed size reference is for testing connectivity in real world conditions—just visiting the page with a clean cache in different conditions gives you a good feel for the user cost of  a known page size.

The static source is available on GitHub but note that some server configuration is required to ensure that the resulting page is exactly the correct size.

UPDATE 21/6/2016: transfer weight changed from 1024 x 1024 to 1,000,000 bytes,

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