Molten Leading

Manually adjusting line-height with media queries for optimum readability across vast number of screen sizes can be hard. What makes it even harder, is, that instead of the screen width, the line-height should be relative to its container’s width and its font settings in order to achieve proper readability and appropriate spacing.

Molten Leading is a tiny JavaScript plugin that automatically adjusts line-height based on element width for optimum readability across vast number of devices.

Thanks to @Wilto, there has been a jQuery plugin called “Molten Leading” around for quite some time already which makes it possible to automate this process and define a minimum width at which the adjustment starts, a maximum element width where it stops, and a minimum and maximum line-height to adjust through.

I wanted to use something similar in one of my latest projects, but I didn’t want to introduce new dependencies to external JavaScript libraries just because of this one feature. I also wanted something that would have a bit better performance, so I decided to write a custom version of Molten Leading without any library dependencies. All this is now available on GitHub too, so take a look and give it a spin.


  • Automatically adjust line-height based on element width.
  • Works in all browsers, including IE6 and up.
  • Uses requestAnimationFrame for the best possible performance.
  • Free to use in both commercial and non-commercial projects.
  • Doesn’t require external JavaScript libraries.
  • Supports px, em and rem CSS units.
  • Weighs only 1.17kb minified and Gzip’ed.
  • Supports multiple instances.

Responsive Line Height


Molten Leading on GitHub

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