CSS Unit Tools
Professional, fast and 100% accurate CSS unit converters for web developers. Convert between pixels, REM, EM, viewport units and more with mathematical precision.
PIXEL (PX)
Convert pixels to other CSS units
PX to REM
Convert pixels to REM units
PX to EM
Convert pixels to EM units
PX to %
Convert pixels to percentage
PX to VW
Convert pixels to viewport width
PX to VH
Convert pixels to viewport height
PX to IN
Convert pixels to inches
PX to CM
Convert pixels to centimeters
PX to MM
Convert pixels to millimeters
PX to PT
Convert pixels to points
PX to PC
Convert pixels to picas
REM
Convert REM to other CSS units
REM to PX
Convert REM units to pixels
REM to EM
Convert REM to EM units
REM to %
Convert REM to percentage
REM to IN
Convert REM to inches
REM to CM
Convert REM to centimeters
REM to MM
Convert REM to millimeters
REM to PT
Convert REM to points
REM to VW
Convert REM to viewport width
REM to VH
Convert REM to viewport height
EM
Convert EM to other CSS units
EM to PX
Convert EM units to pixels
EM to REM
Convert EM to REM units
EM to %
Convert EM to percentage
EM to IN
Convert EM to inches
EM to CM
Convert EM to centimeters
EM to MM
Convert EM to millimeters
EM to PT
Convert EM to points
EM to VW
Convert EM to viewport width
EM to VH
Convert EM to viewport height
POINT (PT)
Convert points to other CSS units
PT to PX
Convert points to pixels
PT to EM
Convert points to EM units
PT to REM
Convert points to REM units
PT to IN
Convert points to inches
PT to CM
Convert points to centimeters
PT to MM
Convert points to millimeters
CENTIMETER (CM)
Convert centimeters to other CSS units
CM to PX
Convert centimeters to pixels
CM to PT
Convert centimeters to points
CM to EM
Convert centimeters to EM units
CM to REM
Convert centimeters to REM units
CM to IN
Convert centimeters to inches
CM to MM
Convert centimeters to millimeters
VIEWPORT WIDTH (VW)
Convert viewport width to other CSS units
VW to PX
Convert viewport width to pixels
VW to CM
Convert viewport width to centimeters
VW to EM
Convert viewport width to EM units
VW to REM
Convert viewport width to REM units
VW to IN
Convert viewport width to inches
VW to MM
Convert viewport width to millimeters
INCH (IN)
Convert inches to other CSS units
IN to PX
Convert inches to pixels
IN to CM
Convert inches to centimeters
IN to MM
Convert inches to millimeters
IN to PT
Convert inches to points
IN to PC
Convert inches to picas
IN to REM
Convert inches to REM units
IN to EM
Convert inches to EM units
IN to %
Convert inches to percentage
VIEWPORT HEIGHT (VH)
Convert viewport height to other CSS units
VH to PX
Convert viewport height to pixels
VH to CM
Convert viewport height to centimeters
VH to EM
Convert viewport height to EM units
VH to REM
Convert viewport height to REM units
VH to IN
Convert viewport height to inches
VH to MM
Convert viewport height to millimeters
PERCENTAGE (%)
Convert percentage to other CSS units
% to PX
Convert percentage to pixels
% to EM
Convert percentage to EM units
% to REM
Convert percentage to REM units
% to VW
Convert percentage to viewport width
% to VH
Convert percentage to viewport height
% to IN
Convert percentage to inches
PICA (PC)
Convert picas to other CSS units
PC to PX
Convert picas to pixels
PC to PT
Convert picas to points
PC to IN
Convert picas to inches
PC to CM
Convert picas to centimeters
PC to MM
Convert picas to millimeters
PC to EM
Convert picas to EM units
MILLIMETER (MM)
Convert millimeters to other CSS units
MM to PX
Convert millimeters to pixels
MM to CM
Convert millimeters to centimeters
MM to IN
Convert millimeters to inches
MM to PT
Convert millimeters to points
MM to PC
Convert millimeters to picas
MM to EM
Convert millimeters to EM units
PAPER SIZE
Paper size converter
A4 → PX
Convert A4 paper size to pixels
Letter → PX
Convert Letter paper size to pixels
Legal → PX
Convert Legal paper size to pixels
A3 → PX
Convert A3 paper size to pixels
A5 → PX
Convert A5 paper size to pixels
How to Convert CSS Units - Complete Guide
Learn how to convert CSS units like a pro developer. Master pixel to REM conversions, viewport units, and responsive design principles with our comprehensive guide.
Choose Your Units
Select the CSS unit conversion tool you need. From px to rem, em to vw, or any other unit combination for your web development project.
Enter Values
Input your CSS values and instantly see accurate conversions. Our tools support all major CSS units including px, rem, em, %, vw, vh, and more.
Copy & Use
Copy the converted values directly to your CSS files. Perfect for responsive design, accessibility improvements, and cross-browser compatibility.
Understanding CSS Units for Modern Web Development
Master responsive design with our comprehensive CSS units reference guide. Learn when to use pixels, REM, EM, viewport units, and percentages for optimal web performance.
Absolute Units vs Relative Units
Pixels (px)
Fixed unit perfect for borders, shadows, and precise positioning. Use for elements that shouldn't scale with user preferences.
REM Units
Relative to root font size. Ideal for typography, spacing, and responsive design. 1rem = 16px by default.
EM Units
Relative to parent element font size. Great for component-based styling and maintaining proportional relationships.
Viewport Units (vw, vh)
Relative to viewport dimensions. Perfect for full-screen layouts, hero sections, and responsive typography.
Best Practices for CSS Unit Selection
- ✓Use REM for font sizes and spacing to respect user accessibility settings
- ✓Use PX for borders, box-shadows, and precise graphic elements
- ✓Use EM for padding/margin in components for scalable design
- ✓Use VW/VH for responsive layouts and fluid typography
- ✓Use percentages for flexible widths and responsive grids
- ✓Combine units strategically for optimal responsive behavior
Frequently Asked Questions About CSS Unit Conversion
Get answers to common questions about CSS units, conversions, and responsive design best practices.
What is the difference between PX, REM, and EM units?
PX (pixels) are absolute units that remain fixed regardless of user settings. REM units are relative to the root element's font size (typically 16px), making them ideal for responsive design. EM units are relative to the parent element's font size, creating scalable components. Use REM for global spacing and typography, EM for component-level scaling, and PX for precise positioning.
How do I convert 16px to REM?
To convert 16px to REM, divide the pixel value by the root font size (default 16px). So 16px ÷ 16 = 1rem. Our PX to REM converter automatically calculates this for you with any custom root font size you specify.
When should I use viewport units (VW, VH)?
Viewport units are perfect for creating full-screen layouts, hero sections, and responsive typography that scales with screen size. Use VW (viewport width) for horizontal scaling and VH (viewport height) for vertical scaling. They're especially useful for mobile-first responsive design.
Are your CSS unit conversions accurate for all browsers?
Yes, our conversion tools use standard CSS specifications and are accurate across all modern browsers. The calculations are based on official W3C standards and work consistently in Chrome, Firefox, Safari, Edge, and other browsers.
How can CSS unit conversion improve accessibility?
Using relative units like REM and EM respects user browser settings for font size, which is crucial for users with visual impairments. When users increase their browser's default font size, REM-based layouts scale proportionally, maintaining readability and usability.
Built for Modern Web Development
Essential tools designed to streamline your CSS workflow and improve code quality across all your projects.
Instant Conversions
Real-time calculations save development time and eliminate manual math errors in your CSS workflow.
Precise Results
Mathematical accuracy based on web standards ensures consistent rendering across all browsers.
Mobile Ready
Responsive interface works seamlessly on desktop, tablet, and mobile for development on any device.
Accessibility First
Multi-language support and accessible design patterns help create inclusive web experiences.