What does that mean in practice?
We're web performance specialists here, we work with measurements and numbers, so we need a more exact number. Numbers reduce ambiguity. To find out that number we need to run the `say` command on a Unix/Mac computer and time the output file.
$ say -o cls.aiff "Cumulative Layout Shift"
Now we open the audio file in music editing software (I'm using Reaper) and observe the timing.
One immutable magic number to rule them all
And here we have the answer. A website should load in 1.722 seconds or less. Whatever load means, it's up to you. But yeah, go make it happen!
A website should load before you can say "Cumulative Layout Shift", in other words in 1.722 seconds or less.
Some overachievers (*cough* Tim Vereecke) are going with the "CLS" abbreviation, instead of the full Cumulative Layout Shift. For these individuals and companies, the magic number is 0.978s or just a second with time to spare. Are you an overachiever?