AscendLab
12 free tools

Free unit, number, CSS, color, and contrast converters

Start by task

I need measurement conversionUse Unit Converter.I need frontend sizingUse CSS Unit Converter or CSS Clamp Generator.I need accessible colorsConvert color values, then check contrast.I need layout CSSGenerate grid or flexbox CSS, then test it in context.

Convert measurement units, number bases, Roman numerals, CSS sizing values, color formats, palettes, gradients, shadows, layouts, and contrast ratios.

Best for quick measurement cleanup, binary and hex conversion, Roman numeral lookup, frontend sizing, fluid typography, responsive spacing, design token work, CSS color conversion, palette generation, grid and flexbox CSS, gradient and shadow generation, and WCAG color checks.

Category

Converters

Access

Free

Data handling note

Converters run arithmetic, CSS, color, contrast, and number-base transformations in the browser. Review rounding, units, accessibility context, and responsive layout before copying output into production.

Last updated

June 30, 2026

Quick answer
Free unit, number, CSS, color, and contrast converters group related browser tools for one practical workflow.

Best for quick measurement cleanup, binary and hex conversion, Roman numeral lookup, frontend sizing, fluid typography, responsive spacing, design token work, CSS color conversion, palette generation, grid and flexbox CSS, gradient and shadow generation, and WCAG color checks.

Open an individual tool page when you need the actual controls, examples, assumptions, FAQs, and related links.

Best inputs
Use Unit Converter.

I need measurement conversion: Use Unit Converter.

I need frontend sizing: Use CSS Unit Converter or CSS Clamp Generator.

Common use cases
Start with the output format: measurement unit, CSS unit, color, contrast, layout CSS, number base, or Roman numeral.

Convert everyday units: Unit Converter

Convert CSS sizing: CSS Unit Converter / CSS Clamp Generator

Search within category
Use these task phrases when you know what you need but not the exact tool name.
unit converterUnit ConverterOpen matchmetric conversion calculatorUnit ConverterOpen matchmetric to imperial converterUnit ConverterOpen matchinches to cm converterUnit ConverterOpen matchpounds to kg converterUnit ConverterOpen matchcelsius fahrenheit converterUnit ConverterOpen matchpx to rem converterCSS Unit ConverterOpen matchrem to px converterCSS Unit ConverterOpen matchcss clamp generatorCSS Clamp GeneratorOpen matchbinary to decimalNumber Base ConverterOpen matchhex to decimalNumber Base ConverterOpen matchroman numeral converterRoman Numeral ConverterOpen matchcolor converterColor ConverterOpen matchhex to rgb converterColor ConverterOpen matchcontrast checkerContrast CheckerOpen matchWCAG contrast checkerContrast CheckerOpen matchcss gradient generatorCSS Gradient GeneratorOpen matchlinear-gradient generatorCSS Gradient GeneratorOpen matchradial gradient generatorCSS Gradient GeneratorOpen matchconic gradient generatorCSS Gradient GeneratorOpen matchbackground gradient generatorCSS Gradient GeneratorOpen matchcss gradient backgroundCSS Gradient GeneratorOpen matchhero background gradientCSS Gradient GeneratorOpen matchbutton gradient cssCSS Gradient GeneratorOpen matchtailwind gradient classCSS Gradient GeneratorOpen matchcopy css gradientCSS Gradient GeneratorOpen matchbox shadow generatorCSS Box Shadow GeneratorOpen matchcss box shadowCSS Box Shadow GeneratorOpen matchbox shadow cssCSS Box Shadow GeneratorOpen matchcard shadow cssCSS Box Shadow GeneratorOpen matchbutton shadow cssCSS Box Shadow GeneratorOpen matchinset box shadowCSS Box Shadow GeneratorOpen matchcopy box-shadow cssCSS Box Shadow GeneratorOpen matchcolor palette generatorColor Palette GeneratorOpen matchcss grid generatorCSS Grid GeneratorOpen matchflexbox generatorFlexbox GeneratorOpen match

Featured tools

Best starting points in Converters

These tools are surfaced from the category decision guide, so they match the most common tasks before the full list below.

Featured
Unit Converter
Convert length, weight, temperature, data size, area, and volume units directly in your browser.
Measurement cleanup
Featured
CSS Unit Converter
Convert px, rem, em, and percent values for responsive CSS using root and parent font sizes.
Frontend sizing
Featured
Color Converter
Convert HEX, RGB, and HSL color values with a live preview and copy-ready CSS formats.
Design tokens
Featured
CSS Grid Generator
Generate responsive CSS grid code with columns, rows, minmax column width, gap controls, browser-side preview, and copy-ready CSS.
Grid layout CSS
Featured
Number Base Converter
Convert integers between binary, octal, decimal, and hexadecimal with browser-side processing.
Binary and hex
Which converter should I use?
Start with the output format: measurement unit, CSS unit, color, contrast, layout CSS, number base, or Roman numeral.
Convert everyday unitsUnit Converter
Open tool

Use this for length, weight, temperature, data, area, volume, and other everyday measurements.

Next: Check rounding before copying a value into specs or docs.

Processing: Browser-side conversion.

Convert CSS sizingCSS Unit Converter / CSS Clamp Generator
Open tool

Use these when moving between px, rem, em, percent, and fluid clamp formulas.

Next: Check the result against actual container and breakpoint behavior.

Processing: Browser-side CSS math.

Convert color or contrastColor Converter / Contrast Checker
Open tool

Use these when design tokens, HEX/RGB/HSL values, and accessibility checks need alignment.

Next: Run contrast against the real foreground and background pair.

Processing: Browser-side color math.

Generate CSS layouts or visual tokensCSS Grid, Flexbox, Gradient, Shadow, Palette tools
Open tool

Use these when the output is CSS that will be copied into a prototype or design system.

Next: Test generated CSS in the target layout before shipping.

Processing: Browser-side CSS generation.

Convert number systemsNumber Base / Roman Numeral Converter
Open tool

Use these for binary, hex, decimal, octal, or Roman numeral lookup and validation.

Next: Keep leading zeros and signed-number expectations explicit when documenting results.

Processing: Browser-side conversion.

Recommended first tool by task
Pick the route that matches the problem you are actually trying to solve.
I need measurement conversionUse Unit Converter.I need frontend sizingUse CSS Unit Converter or CSS Clamp Generator.I need accessible colorsConvert color values, then check contrast.I need layout CSSGenerate grid or flexbox CSS, then test it in context.
Common mistakes
  • Copying rounded values without knowing the precision needed.
  • Checking contrast on a different background than the final UI.
  • Using generated CSS without testing responsive behavior.
  • Mixing binary, decimal, and hex values without documenting the base.
Next workflow paths
Use these when one tool is only part of the job.
SEO Publishing WorkflowUse CSS, color, and URL-adjacent conversion helpers before publishing page assets.Unit Converter docsReview supported unit categories, formulas, and rounding behavior.CSS Clamp Generator docsReview fluid sizing assumptions and when clamp is not the right fit.

Available now

All Converters

Free · Live
Contrast Checker
Check foreground and background color contrast ratios with WCAG AA and AAA pass indicators.
WCAG color check
Free · Live
CSS Box Shadow Generator
Design CSS box shadows for cards, buttons, modals, and inset states with offset, blur, spread, opacity, preview, and copy-ready CSS.
Shadow CSS
Free · Live
CSS Gradient Generator
Create copy-ready linear, radial, and conic CSS gradients with gallery presets, contrast warnings, CSS variables, Tailwind output, and preview.
CSS gradients
Free · Live
Color Palette Generator
Generate tints, shades, complement colors, swatches, and copy-ready CSS variables from a HEX color directly in your browser.
Color tokens
Free · Live
CSS Clamp Generator
Generate responsive CSS clamp() formulas for fluid font sizes, spacing, and layout values from viewport ranges.
Fluid CSS sizing
Free · Live
CSS Grid Generator
Generate responsive CSS grid code with columns, rows, minmax column width, gap controls, browser-side preview, and copy-ready CSS.
Grid layout CSS
Free · Live
Flexbox Generator
Generate flexbox CSS with direction, justify-content, align-items, flex-wrap, gap controls, browser-side preview, and copy-ready code.
Flex layout CSS
Free · Live
Unit Converter
Convert length, weight, temperature, data size, area, and volume units directly in your browser.
Measurement cleanup
Free · Live
CSS Unit Converter
Convert px, rem, em, and percent values for responsive CSS using root and parent font sizes.
Frontend sizing
Free · Live
Color Converter
Convert HEX, RGB, and HSL color values with a live preview and copy-ready CSS formats.
Design tokens
Free · Live
Number Base Converter
Convert integers between binary, octal, decimal, and hexadecimal with browser-side processing.
Binary and hex
Free · Live
Roman Numeral Converter
Convert decimal numbers to Roman numerals and validate Roman numeral input locally.
Roman numerals
Why this category exists
Best for quick measurement cleanup, binary and hex conversion, Roman numeral lookup, frontend sizing, fluid typography, responsive spacing, design token work, CSS color conversion, palette generation, grid and flexbox CSS, gradient and shadow generation, and WCAG color checks.

This page groups related tools for easier browsing, while every individual tool page focuses on the specific workflow and output.

Frequently asked questions

Which conversions are supported?

This category includes everyday units, binary/octal/decimal/hex number bases, Roman numerals, CSS px/rem/em/percent sizing, CSS clamp formulas for fluid type and spacing, HEX/RGB/HSL color formats, color palette generation, CSS grid generation, flexbox generation, CSS gradient generation, CSS box-shadow generation, and WCAG contrast checks.

Do converter results require an account?

No. The current converter tools are free and available directly in the browser.

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