Why should I use REM instead of PX in CSS?

REM units are relative to the root HTML font size. When users increase their default browser font size for accessibility or vision reasons, rem-scaled text and padding scale proportionally, whereas hardcoded px values remain fixed and can cause accessibility violations.

What is the standard base font size for 1rem?

Almost all modern web browsers (Chrome, Safari, Firefox, Edge) default to a 16px base font size, meaning 1rem equals 16px by default.

How does the 62.5% CSS trick relate to rem?

Some developers set html { font-size: 62.5% }, which makes 1rem equal 10px (since 62.5% of 16px is 10px). You can test this scenario easily by selecting the 10px preset in this converter.

What exactly does PX to REM Converter do?

Convert pixels to rem units & Tailwind classes Instantly convert pixels (px) to CSS root units (rem) and vice-versa. Customize root HTML font size, view CSS snippet rules, and consult the visual Tailwind size reference table.

PX to REM Converter

Convert pixels to rem units & Tailwind classes

Free Private No uploads

PX to REM Converter

Root / HTML Base Font Size

Default browser standard is 16px.

Pixels (PX)

Screen & element design pixel value.

Rem Units (REM)

rem

Relative to root HTML font size (16px).

CSS Rulefont-size: 1rem; /* 16px */

PX to REM Reference Table (Base 16px)

Pixels (PX)	Root Units (REM)	Tailwind Utility
8px	0.5rem	-[8px]
10px	0.625rem	-[10px]
12px	0.75rem	text-xs / p-3
14px	0.875rem	text-sm / p-3.5
16px	1rem	text-base / p-4
18px	1.125rem	text-lg / p-4.5
20px	1.25rem	text-xl / p-5
24px	1.5rem	text-2xl / p-6
28px	1.75rem	text-3xl / p-7
32px	2rem	text-4xl / p-8
36px	2.25rem	text-4xl / p-9
40px	2.5rem	text-5xl / p-10
48px	3rem	text-5xl / p-12
64px	4rem	text-6xl / p-16
96px	6rem	-[96px]

100% Private & In-Browser

Processed locally using client-side JavaScript. Your files and data never touch any server.

Instant & Unlimited

No registration, no waiting queues, and no limits on file conversions or generations.

Tool Overview & Guide

What is PX to REM Converter?

The PX to REM Converter transforms pixel dimensions (px) into scalable CSS root units (rem) and vice versa. It enables frontend developers and web designers to implement fluid, accessible, and responsive typography that adapts seamlessly to user browser settings and zoom levels.

Step-by-Step Instructions

How to use PX to REM Converter

Set your root HTML base font size (standard browser default is 16px).

Enter a value in either the Pixels (px) or Rem (rem) input field.

The tool calculates the two-way conversion instantaneously with live preview.

Copy the generated CSS font-size rule or check the Tailwind CSS mapping table.

Key Capabilities

Instant two-way conversion between PX and REM
Customizable root base size with quick 10px, 14px, and 16px presets
Ready-to-use CSS code snippet generator with one-click copy
Comprehensive reference table matching pixels, rem, and Tailwind utility classes

Common Use Cases

Converting Figma, Sketch, or Adobe XD pixel designs into responsive rem CSS.
Building accessible web interfaces that respect user browser font preferences.
Looking up exact Tailwind CSS spacing and typography utility classes (p-4, text-xl, etc.).
Refactoring legacy pixel-based stylesheets into modern rem units.

Clear Answers

Frequently Asked Questions

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