Note: This site is currently "Under construction". I'm migrating to a new version of my site building software. Lots of things are in a state of disrepair as a result (for example, footnote links aren't working). It's all part of the process of building in public. Most things should still be readable though.

Does CSS Minification Matter? (Does 1-2KB?)

Here's how many bytes you'll save by minifying the files of three different CSS frameworks and the primary CSS file on my site: 

File            Raw   gzip6   gzip9  brotli

bootstrap   145,933  21,287  20,964  16,945
min         121,457  19,754  19,604  16,036
_________   _______  ______  ______  ______
diff         24,476   1,533   1,360     909


bulma       245,486  29,637  29,435  21,886
min         207,302  27,596  27,452  21,000
_________   _______  ______  ______  ______
diff         38,184   2,041   1,983     886


foundation  196,222  21,784  21,633  16,836
min         159,374  19,269  19,237  15,532
_________   _______  ______  ______  ______
diff         36,848   2,515   2,396   1,304


my-site      18,897   2,520   2,500   2,106 
min          13,991   1,977   1,973   1,680
_________   _______  ______  ______  ______
diff          4,906     543     527     426


                        All values in bytes

Where It Started

Serious question: Do we *really* need to minify our JS and CSS files?

Does it matter at all if we're gzipping the HTTP streams anyway?

I was

What Matters (Your Choice)

The question to define is what you mean by what matters. I leave that as an exercise for the reader. As you can see from the data above, assuming you use some kind of compression, the difference in size between minified and the full size version of the files is between: 0.426 - 2,515KB.

My Choice

I'm writing my own

Your mileage may vary.

Notes

  • The question is about about minifying. I'm not going into the diffs between minified-compressed vs uncompressed-unminified files. You're server probably already compresses and if it doesn't it's probably worth turning that on

  • I haven't tested how having lots of comments in your CSS would change things. It certianly would to some degree, but that's also an exercise for the reader

  • I didn't do Tailwind because I didn't see a trivial way to get a full version of the framework as a raw file

  • gzip can go from levels 1-9 with 9 being the best compression. The default is 6. Figuring out what level your servers compresses is an adventure I leave to you

  • brotli is a compression that Google came up with. I'd never heard of it before. I learned about it via a mention in the Mastodon thread. Something else to investigate

References