PX to REM Converter
PX to REM Converter
Convert pixels to REM units for responsive CSS - free online converter with base size calculator
/* Convert 16px to REM (base: 16px) */
/* Formula: 16px ÷ 16px = 1rem */
font-size: 1rem;
margin: 1rem;
padding: 1rem;
gap: 1rem;
/* Common conversions with 16px base */
/* 12px = 0.75rem */
/* 16px = 1rem */
/* 24px = 1.5rem */
/* 32px = 2rem */What is PX to REM Converter?
PX to REM converter is an essential online tool for front-end developers building responsive, accessible websites. REM (Root EM) is a relative CSS unit that scales based on the root element font size, unlike pixels which remain fixed regardless of user preferences. When users increase their browser default font size for accessibility, REM-based layouts scale proportionally while pixel-based designs break. This PX to REM calculator converts any pixel measurement to REM units using your specified base font size (browser default is 16px). Use it to convert font-size, margin, padding, gap, width, and any CSS property from static pixels to flexible REM units. Professional developers rely on REM for typography scales, spacing systems, and component libraries that work across all devices and respect user accessibility settings.
How to Use This Tool
Enter the pixel value you want to convert
Set your base font size (default is 16px, the browser default)
The REM value is calculated instantly: px ÷ base = rem
Copy the REM value to use in your CSS
Apply to font-size, margin, padding, or any CSS property
Examples
Features
- Convert pixels to REM instantly with any base font size
- Customize base size (10px, 16px, 18px, or any value)
- See the PX ÷ base = REM formula explained
- Copy REM values ready for CSS with one click
- Calculate precise decimal REM values automatically
- Real-time conversion updates as you adjust sliders
- Essential for responsive web design and accessibility
- Free PX to REM calculator with no signup required
Frequently Asked Questions
- How do I convert PX to REM for responsive CSS design?
To convert PX to REM, divide your pixel value by the base font size (default 16px). For example: 24px ÷ 16px = 1.5rem. Our PX to REM converter does this automatically. In your CSS, ensure html { font-size: 16px; } (or your chosen base), then use REM values for font-size, margin, padding, and gap properties to create responsive layouts.
- Why should I use REM instead of pixels for web accessibility?
REM units improve web accessibility because they scale when users change their browser default font size. Users with visual impairments often increase font size to 150-200%. With REM-based designs, your entire layout scales proportionally. Pixel-based layouts ignore user preferences, breaking accessibility. WCAG guidelines recommend relative units like REM for accessible typography.
- What is the default base font size for PX to REM conversion?
The browser default base font size is 16px, meaning 1rem equals 16px. Common conversions: 12px = 0.75rem, 14px = 0.875rem, 18px = 1.125rem, 24px = 1.5rem, 32px = 2rem. Some developers set html { font-size: 62.5%; } to make 1rem = 10px for easier mental math (10px, 12px = 1rem, 1.2rem).
- What is the difference between REM and EM units in CSS?
REM (Root EM) always references the html root element font size, providing consistent sizing throughout your site. EM references the parent element font size, causing compounding: a 1.2em inside another 1.2em becomes 1.44x the root. Use REM for predictable, maintainable sizing. Use EM only for components that should scale relative to their context, like button padding.
- Can I use this PX to REM converter for Tailwind CSS spacing?
Yes, our PX to REM converter helps when customizing Tailwind CSS. Tailwind uses REM by default (p-4 = 1rem = 16px). When adding custom spacing to tailwind.config.js, convert your pixel designs to REM. For example, a 30px margin becomes 1.875rem. Add it as spacing: { "7.5": "1.875rem" } for consistent responsive behavior.
- Is it better to use PX or REM for CSS media queries?
Both work for media queries, but they behave differently. PX breakpoints (max-width: 768px) stay fixed regardless of user font size. REM breakpoints (max-width: 48rem) adapt when users zoom or change font size, potentially triggering earlier. Most frameworks use PX for breakpoints. Choose based on whether your breakpoints should respond to user font preferences.