CSS Unit Calculator
Convert between px, rem, em, vw, vh, vmin, vmax with live preview
Convert between CSS units with real-time preview, accessibility compliance checking, and batch conversion. Perfect for developers, designers, and AI-assisted workflows. Export results to CSS, SCSS, or Less files.
Live Preview
See results visually
Accessibility
WCAG compliance check
Batch Mode
Convert multiple values
Export Ready
CSS/SCSS/Less output
Absolute pixels - fixed size regardless of context
Context Settings:
Viewport size in px
Conversion Mode
Common Use Cases
Typography Scale
Common font sizes for web typography
Layout Spacing
Consistent spacing values for layouts
Responsive Sizing
Viewport-based responsive units
Rem vs Em
Use rem for consistent sizing relative to root font. Use em when you want sizing relative to parent element.
Viewport Units
vw/vh are perfect for responsive design.vmin/vmax help create square elements and maintain aspect ratios across devices.
AI Workflow
When AI gives you CSS in px, convert to rem for better accessibility and responsive behavior.
Perfect for Modern Builders
AI-Assisted Development
Perfect when AI tools like ChatGPT give you CSS in pixels but you need rem, em, or viewport units for better responsive design.
💡 Convert AI-generated CSS from px to rem for accessibility and responsive scaling
Responsive Web Development
Calculate and convert between units for responsive layouts, typography scales, and cross-device compatibility.
💡 Convert fixed pixel values to flexible viewport units for mobile-first design
Design System Implementation
Perfect for Webflow, Figma, or no-code builders who need to convert design tokens between different unit systems.
💡 Convert design system spacing from px to rem for consistent scaling across components
How It Works
Step-by-Step Process
Responsive Examples
Frequently Asked Questions
What types of tools does BuilderTools.dev offer?
We provide specialized micro-tools for data conversion, AI development, CSS calculations, API cost estimation, and project planning. All tools are designed to work seamlessly with modern development workflows including AI-assisted building and no-code platforms.
Are BuilderTools.dev tools free to use?
Yes! All our basic tools are completely free with no registration required. We're building premium features for power users, but our core mission is providing essential utilities that every builder can access instantly.
How do these tools help with AI-assisted development?
Our tools are optimized for AI workflows. Convert data to AI-friendly formats, estimate API costs before building, validate AI outputs, and handle technical calculations while you focus on prompting and creating.
Can I integrate BuilderTools with my existing workflow?
Absolutely! Our tools work great with ChatGPT, Claude, Zapier, Make, Bubble, Webflow, and traditional development environments. Copy-paste results anywhere or use our upcoming API for programmatic access.