Why Using rem Units Improves Web Design: A Guide to Better Accessibility

by Mylene — 4 minutes

Why You Should Seriously Love rem (and Let Go of Pixels)

In the ever-twisting, always-changing world of web design, one thing’s for sure: if you blink, you’re outdated. Between flashy animations, dark mode debates, and a million screen sizes, it’s easy to forget the basics.

Like units of measurement.

So today, let’s talk about one of the most underrated web design heroes: rem.

What the heck is rem, anyway?

rem stands for root em — a relative unit based on the font size of the root (<html>) element. Not scary. Actually, kinda genius.

Because once you get the hang of it, rem makes your site more accessible, more consistent, more responsive, and way easier to maintain. Let’s break it down.

Accessibility: The Unsung Power of rem

Picture this: your grandpa opens your site, only to be met with tiny 14px text. No chance he's reading that. But if your layout uses rem? Boom — he cranks up his browser font settings, and the whole site scales with it.

This isn't just about comfort. It’s a core accessibility principle.

According to the official WCAG Guidelines, users should be able to scale text up to 200% without losing content or functionality. And rem makes that effortless.

📢 Accessibility isn’t a bonus — it’s a baseline. And rem helps you meet it.

Consistency Is Queen 👑

Designs built with rem feel more uniform because everything is anchored to the same root value. No more chasing random px values across your stylesheets.

According to the Nielsen Norman Group, visual consistency helps users navigate faster and reduces their cognitive load. Translation: your users don’t have to think about how to use your site — they just do.

✨ Bonus tip: Set your root font size to 62.5% (aka 10px), and suddenly 1.6rem = 16px. Simple math, beautiful results.

Responsiveness Made Easy

You want your site to look good on everything — from a smartwatch to a spaceship dashboard. Using rem helps your layout scale gracefully by tying sizes to one flexible value: the root font size.

Need your entire UI to shrink a little on small screens? Just update your root font size via a media query. No more hunting down every button or input field.

Maintenance Without Tears

One of the most beautiful things about rem: you only need to change one thing to update a design globally.

Want everything 10% bigger? Adjust your root font size. That’s it. No find-replace chaos in your CSS. No weird side effects. Just clean, maintainable styles.

Future-Proofing Like a Pro

The web changes fast — devices, preferences, standards. But when your layout scales with rem, you’re already prepared.

And let’s not forget performance. Faster load times = better user experience = higher conversions. A joint study by Google and Deloitte found that just 0.1 seconds of delay can reduce conversions by up to 8%.

👉 Want more on how to visibly speed up your site? Check out my blog:
How Critical CSS Supercharges Perceived Speed

TL;DR — Why rem Rocks

Here’s why you should stop pixel-pushing and embrace rem:

  • ✅ Makes your site more accessible
  • ✅ Creates visual consistency
  • ✅ Keeps things responsive
  • ✅ Easier to scale and maintain
  • ✅ Future-proofs your design
  • ✅ Boosts performance and UX

So yeah — rem isn’t just “a nice idea.” It’s the quiet MVP of modern, human-friendly web design.

Wanna See It in Action?

Here’s a live example to play with:
👉 CodePen demo: rem in action

Sources that Back This Up (I Swear I Didn’t Make It Up)

Got thoughts? Using rem already? Still clinging to your px? I’d love to hear how you’re handling it in your projects!

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