5 Differences Between the Sass and LESS Preprocessors

Coke or Pepsi, Mac or PC, Marvel or DC. In every community, there’s a debate over which is better. For web designers or developers, that debate is Sass or Less.

What Are Sass and LESS?

Syntactically Awesome Stylesheets (Sass) and Leaner CSS (LESS) are both CSS preprocessors.

Basically, they are special stylesheet extensions that make designing easier and more efficient. Both Sass and LESS then compile into CSS stylesheets so that browsers can read them (because modern browsers cannot actually read .sass or .less file types).

In short, if you plan on being in the world of web development, it’s a good idea to be well-versed in either one of the two. Or even both.

When it comes down to it, both are virtually the same. They make writing CSS simpler, more object-oriented, and just a more enjoyable experience. Nonetheless, there are a few key differences. Below are five of them. 

Sass Is in Ruby, LESS Is in JavaScript

Designers reviewing ideas on desktop computer
Shannon Fagan/Getty Images

Sass is based in Ruby and therefore requires a Ruby install. This is no big deal if you have a Mac. However, it is a couple extra seconds of installation if you have a Windows machine.

LESS was constructed in Ruby like Sass but has been ported to JavaScript. In order to use LESS, you just upload the applicable JavaScript files to your server or compile the CSS sheets through an offline compiler.

To assign variables: Sass uses $, LESS uses @

Both Sass and LESS use specialized characters to assign variables. This way you don’t have to keep entering specifications, you can just enter the character.

In Sass, it’s the dollar sign ($). In LESS, it’s the at symbol (@). The only downside for LESS is that there are a few existing CSS selectors that already use @, so it may stiffen the learning curve a bit, not terribly so.

Sass Has Compass, LESS Has Preboot

Sass and LESS have extensions available to integrate mixins (the ability to store and share CSS declarations throughout a site):

  • Sass has Compass available for mixins, which includes every option available with updates for future support.

  • LESS has Preboot.less, LESS Mixins, LESS Elements, gs, Frameless, etc. LESS’s software support is a bit more fragmented than Sass, resulting in a lot of different options for extensions that may not all function the same way. For your project, you may need all of the above extensions to get a similar performance to Compass.

LESS Has Better Error Messages Than Sass

In this Hongkiat article, both Sass and LESS were tested for their ability to report errors in syntax. The author of the article found that LESS had more accurate error messages in that it reported the correct location of the error.

Something like this could save a bit of time sweating over a typo.

LESS Has More User-Friendly Documentation Than Sass

The LESS documentation is more visually appealing and easier to follow for first-time users. The Sass documentation has much more of a knowledge base or wiki setup.

This is a fact that could be important to the adoption rates of either Sass or LESS since it is a platform designed for use in website design.


There are many people who will hotly debate Sass or LESS because they feel it makes their job easier. However, the answer to this debate is that there really is no right answer between these two syntaxes at this time. What's more important is your personal preference: so consider both and make a decision that is right for you. It's much more valuable to gain the experience than it is to take a side.

Find Your Next Job

Job Search by