25 Free Web-Based Apps & Tools For Working With CSS

We’ve collected 25 small web-based apps and tools that will in one way or another offer quick solutions to many of those frustrating and time-consuming tasks you will often have to overcome when working with CSS.

There are apps that will calculate EM sizes from PXs, tools for minimizing and cleaning your CSS, resources for generating CSS animations, converters for turning images into base64 encoded strings, generators for creating Flexbox layouts, and much more.

You may not need them today, but they are all worth bookmarking, as you just never know when you will need them.

Visual Guide to CSS3 Flexbox Properties

Rather that explaining how the flex properties work, this visual guide focuses on how the flex properties affect layouts.


extractCSS is a tool for extracting ids, classes and inline styles from an HTML document and then outputting them as a CSS stylesheet.

CSS Beautifier

CSS Beautifier will automatically format your CSS styles so that they are consistent and easier to read.


CSScomb is a coding style formatter that will sort CSS properties into a specific pre-configured order.


Just like CSScomb and CSS Beautifier above, ProCCSer offers formatting functionalities, but does give you far more control over the output.

CSS Compressor

CSS Compressor is a handy little app that will minimize and compress your CSS.


StyleStats is a little tool (and Node.js library) for collecting useful CSS stats from any stylesheet. Just input the URL and click ‘parse’.

CSS Trashman

CSS Trashman examines your site’s live DOM and reverse engineers a new, more elegant definition that captures styles down to the pixel. The generated CSS (or Sass) will be customized for your site and ready to be downloaded and dropped into place.

Live CSS Editor

Live CSS Editor is a Chrome and Safari extension that allows you to freely write CSS rules on any site and instantly see the results.

Purify CSS

Purify CSS is a handy tool that detects which CSS selectors your app is using and creates a file without unncessary CSS.

CSS Gradient Animator

CSS Gradient Animator is, as the name suggests, a handy little tool for quickly generating CSS gradients.


px-em is a really, really small tool that will work out the EM sizes from PXs. Just add the parent PX size in the box, the required size in the bottom and you’re done.


RQRWDC (Really Quick Responsive Web Design Calculator) is a responsive web design tool that allows you to work out an elements width in % from PX.


Fibonacci is a really handy generator for creating Flexbox layouts.

Flat UI Color Picker

This is a huge collection of inspiring flat UI colors that you can easily copy and paste into your own stylesheet.


PatternBolt is a collection of SVG patterned backgrounds, packed into a single CSS/SASS file.

CSS Animation Generator

This is a tool for quickly generating small CSS animations. Just copy and paste the generated CSS and HTML into your own project.

CSS Shorthand Generator

Shrthnd is a handy tool that converts CSS properties into shorthand, making shorter and more readable stylesheets.


iconizr is a tool for converting SVG images into a set of CSS icons.


CSSynth is a handy little app that will help to run CSS animations in order.

Create CSS3

Create CSS3 is an app that allows you to generate all of the CSS3 code you will ever need quickly and easily, with fallbacks where required.


Flexplorer is a simple tool for generating flexbox code for lists.

Duri.me – DataURI Converter

Duri.me is a Data URI converter that will turn images into base64 encoded strings that can then be inputted directly in your HTML and CSS files.

CSS Shapes Editor

CSS Shapes Editor is a Chrome extension that offers controls to create and edit CSS Shapes values like polygon(), circle() and ellipse() on any selected element.

Gridpak Responsive Grid Generator

Gridpak is a useful tool for generating a responsive grid system. It gives you control over every aspect of the grid from column padding to where ‘break points’ occur.

CSS Diner

CSS Diner is a simple little game that will help you learn about CSS selectors. All you have to do is type in the correct selector to complete each level. Go on, give it a try.

Also Worth Mentioning:

Featured Image Source: CSS3 2 by RightStuffDesign.