Pixel to REM: What are the differences between the units

Alexandre Teillet
Webflow tips

We all know how essential responsive design is nowadays. With a myriad of different screen sizes to take into account, it's imperative to make our websites as flexible as possible. In this spirit, today we are looking at a key topic: the conversion of Px to REM.

Understanding CSS units: Px and REM

Before we dive into conversion, let's clear things up a bit. In the CSS universe, the pixel (Px) and REM are two commonly used units of measurement. A pixel represents a fixed unit, while REM is a relative unit based on the base font size of the document or browser.

Why use the REM unit instead of PX?

So why would you want to convert your precious pixels into REM? The answer is simple: for better adaptability. The use of the REM unit offers significant advantages for responsive design. Thanks to its relative nature, REM allows your design to effectively adapt to various text size and screen size settings.

How to convert Px to REM: detailed steps

Now let's get to the conversion process. First, you need to determine the base font size. In most browsers, this size is 16px by default. Then, to convert a measure from Px to REM, simply divide the size in pixels by the base font size. For example, to convert 32px to REM, you would do 32/16, which would be 2REM.

Online tools to convert Px to REM

If you prefer a more automated approach, there are plenty of online tools to convert Px to REM. These tools are a quick and easy way to make conversions, especially if you're working with a lot of different metrics. However, it's always helpful to understand the conversion process to fine-tune your design.

Here is a conversion chart to help you.

px rem
1 0.0625
2 0.125
4 0.25
8 0.5
16 1
32 2
64 4
128 8

What unit for Responsive?

In the constantly evolving world of web design, the question of the best unit to use for responsive design is frequently asked. Historically, the pixel has long been the preferred unit of measure in CSS style sheets to define the size of elements. However, with the explosion in the variety of display devices and screen resolutions, sticking to pixels alone can pose problems in terms of adaptability. That's where the REM unit comes in. The REM, which stands for “Root Element,” is a relative unit based on the base font size specified for the HTML document. Instead of setting a fixed size in pixels, the REM adjusts the size according to the base font size. This means that if the base font size changes, all values set in REM will adjust proportionally. By using units like REM in CSS, designers can ensure greater flexibility and adaptability of their designs across a variety of devices, while maintaining the intended aesthetics and functionality. So, while the pixel remains a useful unit for certain specific tasks, the REM has become a preferred choice for those looking to create truly responsive web experiences.

Tips for efficient Pixel to REM conversion

Finally, here are some tips for using REM effectively. First, remember that REM is based on base font size. So be sure to take this metric into account when converting. Second, avoid using values that are too precise in REM. This can lead to element sizes that seem random and inconsistent.

Managing pixels and REM in Webflow

Webflow is a popular platform for website design that offers solid support for Pixels and REM units. Managing these units in Webflow is simple and intuitive. The interface allows you to choose which unit you want to use for each element of your design. By using REM in Webflow, you can easily create a responsive design that adapts to the different screen sizes and text size preferences of your users. Webflow also has built-in tools (division) to help you convert sizes from Px to REM, making the process even easier.

Gestion des REM sur Webflow
Using the REM unit in Webflow


That's it, you are now armed to convert your pixels into REM! We hope that this guide will help you improve the adaptability of your designs. Feel free to share your experiences and ask questions in the comments below. Happy conversion!