What is the default base size?

Most browsers have a default font size of 16px. This means 1rem = 16px unless modified in the CSS of the html element.

Why use REM instead of PX?

REM units are scalable and accessible. They allow users to change their browser's default font size settings, and the website layout will adjust accordingly, unlike fixed pixels.

Free Pixel to REM Converter

Why use REM instead of Pixels?

In modern web development, using relative units like REM (Root EM) is crucial for accessibility and responsiveness. Unlike Pixels (px), which are fixed units, REM units scale based on the root font size defined in the browser or the HTML tag.

Benefits of REM

Accessibility: Users who adjust their browser's default font size for better visibility will see your website scale correctly if you use REMs. Pixel-based sites ignore these user settings.
Maintainability: Change the font size on the `html` tag, and spacing/sizing across your entire application adjusts proportionally.
Responsive Design: REMs make it easier to scale typography and layout elements across different screen sizes using media queries on the root element.

How to Use

1. Set Base Size

The default browser font size is 16px. Ensure the "Base Size" input is set to 16 (or your custom base).

2. Enter Pixel Value

Type the pixel value from your design file (Figma, Sketch) into the "Pixels" field.

3. Copy Result

Click the copy icon next to the REM or EM value and paste it into your CSS.

Industries & Use Cases

This tool is indispensable for professionals in the digital space:

Frontend Developers

Translating design specs into accessible CSS code efficiently.

UI/UX Designers

Understanding how pixel-perfect designs translate to code.

Accessibility Auditors

Ensuring websites meet WCAG guidelines for text resizing.

The Math Behind It

The calculation is straightforward: Pixels / Base Size = REM.

Base Size: Usually 16px (browser default).
Example: 24px / 16px = 1.5rem.

REM vs. EM

REM (Root EM)

Relative to the root (html) element font size. Consistent across the entire page. Best for font sizes, margins, and padding.

EM

Relative to the parent element's font size. Good for component-level scaling (e.g., padding inside a button scaling with the button text).

FAQ

Frequently Asked Questions

Should I set base size to 62.5%?

This is a common trick (16px * 62.5% = 10px) to make math easier (e.g., 1.4rem = 14px). However, modern development often prefers sticking to the 16px standard to avoid confusion with third-party libraries.

Can I use decimals in pixels?

Yes, browsers can render sub-pixel values (e.g., 14.5px). This tool supports decimal inputs for precise conversion.

What is 1rem in pixels?

By default, 1rem equals 16px in most browsers. However, this depends on the user's browser settings and the site's base font-size configuration.

Pixel to REM Converter