Online Tools for CSS Optimization

Cascading Style Sheets or CSS is a web standard for styling your website design. While it is extremely useful and relatively easy, it might use a lot of resources from your website hosting server.

For every website designer, CSS optimization is the important thing. By optimizing your .CSS files, you might highly cut your website bandwidth and speed up your website response time.

Online CSS Optimization Tools
So, there we are going to list and test the best online CSS optimization tools you can use completely free of charge. Optimize your CSS files easily within a seconds.

How does this work?

Basically, CSS is wrote in lines and these tools are able to cut these lines and combine several similar styles into one. This automatically means that output is smaller – and smaller file size means faster load and better response.

Let’s take this CSS code as example:

#class {
   background-color: #4E4E4E;
   padding-left: 10px;
   padding-right: 10px;
   padding-top: 15px;
   padding-bottom: 25px;
#class a {
   margin-top: 10px;
   margin-bottom: 20px;

This above CSS line can be optimized to look like the code below and still have the exact same output but with 45% less output:

#class{color:#fff;background-color:#4E4E4E;padding:15px 10px 25px;}
#class a{color:#000;margin-top:10px;margin-bottom:20px;}

As you can see, the optimized code snipped is obviously smaller than the original one. The only downside of this is readability and it might be harder to find the styles you are looking for later.

Best Online CSS Optimization Tools
I have tested my CSS file for testing all these CSS optimization tools at their optimization modes. In the table below, I am going to show you the results for all compression levels supported.

For the test, I used by own style.css from this website. The default (uncompressed) size is exactly 43.943 KB.

CSS Tool NameMinimum Compression (%)Standard Compression (%)High Compression (%)
Clean CSS24.827.731.9
CSS Tidy20.120.120.1
CSS Compressor25.527.732.6
Code Beautifier22.426.931.7
Devilo US8.612.414.3
Table: Best online CSS optimization tools with Low, Medium and High compression level results.

As you can see, compression level might be pretty amazing. The top 3 CSS optimization tools from this table are:

1. CSS Compressor (avg. 28.6% compression)
2. Clean CSS (avg. 28.2% compression)
3. Code Beautifier (avg. 27% compression)

Looks like all these three tools works on the same compression engine and that is why these results are so close. CSS Tidy is also another popular optimization tool, but as you can see all three compression levers give the same output for my test CSS file.