Pixel to REM: What are the differences between the units?

Alexandre Teillet
Webflow tips

We all know how essential responsive design is these days. With a myriad of different screen sizes to consider, it's imperative that we make our websites as flexible as possible. With this in mind, today we're taking a look at a key topic: converting Px to REM.

Understanding CSS units : Px and REM

Before we dive into the conversion, let's clarify a few things. In the CSS world, 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 basic font size of the document or browser.

Why use REM instead of PX?

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

How to convert Px to REM: detailed steps

Let's move on to the conversion process. First of all, we need to determine the basic font size. In most browsers, this size is 16px by default. Then, to convert a measurement from Px to REM, simply divide the size in pixels by the size of the base font. For example, to convert 32px to REM, you would do 32/16, which would give 2REM.

Online tools to convert Px to REM

If you prefer a more automated approach, there are many online tools for converting Px to REM. These tools are a quick and easy way to make conversions, especially if you're working with many different measurements. However, it's always useful to understand the conversion process to fine-tune your design.

Here's a conversion table 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 ever-changing 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 measurement in CSS style sheets for defining element size. 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. REM, which stands for "Root Element", is a relative unit based on the base font size specified for the HTML document. Instead of defining a fixed size in pixels, REM adjusts the size according to the size of the base font. This means that if the base font size changes, all values defined 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 retaining the intended aesthetics and functionality. So, while the pixel remains a useful unit for certain specific tasks, 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 a few tips on how to use REM effectively. First, remember that REM is based on the basic font size. So be sure to take this into account when converting. Secondly, avoid using values that are too precise in REM. This can lead to element sizes that appear random and inconsistent.

Managing pixels and REM in Webflow

Webflow is a popular web design platform that offers solid support for Pixels and REM units. Managing these units in Webflow is simple and intuitive. The interface lets you choose the 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 Px sizes to REM, making the process even easier.

REM management on Webflow
Using the REM unit in Webflow


Now you're ready to convert your pixels into REM! We hope 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 converting!