9 min readby PixHue Team

HEX vs RGB vs HSL vs OKLCH — Which Color Format Should You Use?

A practical comparison of HEX, RGB, HSL, and OKLCH color formats. Learn the strengths, limitations, and ideal use cases for each format in modern web design.

color formatsHEXRGBHSLOKLCHCSS

Every web designer and developer encounters the same question early in their career: which color format should I use? HEX codes are everywhere, RGB feels familiar, HSL promises readability, and OKLCH is the new contender claiming perceptual superiority. The truth is that each format excels in different situations, and understanding their tradeoffs will make you a better color practitioner.

This guide provides a thorough, practical comparison to help you choose the right format for every situation.

Quick Comparison Table

Feature HEX RGB HSL OKLCH
Syntax #7c3aed rgb(124, 58, 237) hsl(262, 83%, 58%) oklch(0.53 0.26 293)
Readability Low Medium High High
Opacity support 8-digit hex rgba() hsla() oklch(L C H / A)
Perceptually uniform No No No Yes
Wide gamut No No No Yes
CSS support Universal Universal Universal Modern browsers
Easy to manipulate No Difficult Yes Yes
Design tool support Universal Universal Universal Growing

HEX — The Universal Shorthand

What It Is

HEX (hexadecimal) encodes color as a six-character string prefixed with #. Each pair of characters represents the red, green, and blue channel as a value from 00 to FF (0–255 in decimal).

color: #7c3aed;        /* violet */
color: #7c3aed80;      /* violet at 50% opacity (8-digit hex) */
color: #fff;           /* shorthand for #ffffff */

Strengths

  • Universally supported — every design tool, browser, and programming language understands HEX codes
  • Compact — six characters encode a full color, making it efficient for storage and communication
  • Industry standard — brand guidelines, style guides, and design specs universally use HEX
  • Copy-paste friendly — easy to share in Slack, Figma, or documentation

Limitations

  • Not human-readable — #7c3aed tells you nothing about the color's appearance without memorization or tooling
  • Difficult to manipulate — want to make a color 20% lighter? You can't do it mentally with HEX
  • sRGB only — cannot express colors outside the sRGB gamut
  • No perceptual basis — similar HEX codes can look very different, and different codes can look nearly identical

When to Use HEX

HEX is ideal for storing and communicating specific color values. Use it in design tokens, brand guidelines, and anywhere you need an unambiguous color reference. If you need to convert from HEX to any other format, PixHue's Color Converter handles it instantly.

RGB — The Machine's Language

What It Is

RGB (Red, Green, Blue) defines color using three additive light channels, each ranging from 0 to 255. It directly maps to how screens produce color — each pixel contains red, green, and blue sub-pixels whose intensities combine to create the visible color.

color: rgb(124, 58, 237);           /* violet */
color: rgb(124 58 237 / 0.5);       /* modern syntax with opacity */
color: rgba(124, 58, 237, 0.5);     /* legacy syntax with opacity */

Strengths

  • Maps to hardware — RGB values directly control pixel sub-pixel intensities
  • Transparent calculations — mixing, interpolation, and blending operations are mathematically simple
  • Universal support — supported everywhere since CSS1
  • Precise — 256 × 256 × 256 = 16.7 million exact colors

Limitations

  • Non-intuitive — "make the violet a bit warmer" doesn't translate to obvious channel adjustments
  • Non-perceptual — equal numeric steps don't produce equal visual steps
  • sRGB constrained — like HEX, limited to the sRGB gamut
  • Verbose — three numbers are harder to scan than a HEX code

When to Use RGB

RGB is ideal for programmatic color operations — canvas drawing, WebGL shaders, image processing, and any context where you're directly manipulating pixel data. It's also the best format when working with APIs that expect channel values.

HSL — The Designer's Favorite

What It Is

HSL (Hue, Saturation, Lightness) represents color in terms more intuitive to human thinking. Instead of mixing red, green, and blue intensities, you specify what color (hue), how vivid (saturation), and how bright (lightness).

color: hsl(262, 83%, 58%);          /* violet */
color: hsl(262 83% 58% / 0.5);      /* with opacity */
  • Hue: 0°–360° on the color wheel (0 = red, 120 = green, 240 = blue)
  • Saturation: 0% (gray) to 100% (fully vivid)
  • Lightness: 0% (black) to 100% (white), with 50% being the "pure" color

Strengths

  • Intuitive model — you can read hsl(262, 83%, 58%) and understand it's a vivid, medium-brightness violet
  • Easy manipulation — want a lighter version? Increase lightness. Desaturated? Decrease saturation
  • Good for theming — hue rotation and lightness adjustment make theming straightforward
  • Widely supported — every modern browser and most design tools support HSL

Limitations

  • Perceptually non-uniform — and this is the critical flaw. An HSL yellow at 50% lightness appears far brighter than a blue at 50% lightness. "Equal numbers" do not mean "equal perception"
  • Unreliable for accessibility — you can't trust lightness values for contrast decisions across different hues
  • sRGB only — cannot express Display P3 or wide-gamut colors
  • Saturation is misleading — 100% saturation at very high or low lightness levels produces colors that don't look "saturated" at all

For a deep dive into why this matters, see our guide on the OKLCH color space.

When to Use HSL

HSL remains excellent for quick color exploration and simple theming in sRGB contexts. Use it when you need to rapidly experiment with hue shifts or lightness adjustments and perceptual accuracy isn't critical. It's also great for explaining color relationships to non-technical stakeholders.

OKLCH — The Perceptual Standard

What It Is

OKLCH (OK Lightness Chroma Hue) is a perceptually uniform color space that ensures equal numeric changes produce equal visual changes. It's based on the Oklab model and represents a genuine advancement in how we work with color.

color: oklch(0.53 0.26 293);         /* violet */
color: oklch(0.53 0.26 293 / 0.5);   /* with opacity */
  • L (Lightness): 0 (black) to 1 (white), perceptually linear
  • C (Chroma): 0 (gray) to ~0.4 (maximum colorfulness), unbounded
  • H (Hue): 0°–360°, perceptually uniform spacing

Strengths

  • Perceptually uniform — the defining advantage. Equal lightness values look equally bright across all hues
  • Wide gamut — can express Display P3, Rec. 2020, and beyond
  • Reliable for accessibility — lightness differences map predictably to contrast
  • Consistent palette generation — evenly spaced values produce visually even scales
  • CSS native — supported in Chrome, Firefox, Safari, and Edge

Limitations

  • Newer format — some older tools and libraries don't support it yet
  • Chroma is unfamiliar — the 0–0.4 range feels different from HSL's 0%–100% saturation
  • Gamut awareness required — high chroma values at extreme lightness levels may be clipped in sRGB displays
  • No legacy browser support — IE11 and very old browsers don't understand oklch()

When to Use OKLCH

OKLCH is ideal for professional color work — building design systems, generating accessible palettes, creating themes with consistent contrast, and any context where perceptual accuracy matters. It's the best choice for new projects without legacy constraints.

Practical Decision Framework

Use HEX when:

  • Storing final color values in config files or databases
  • Sharing colors with collaborators via text
  • Working within systems that only accept HEX input
  • Writing brand guidelines or design spec documents

Use RGB when:

  • Doing programmatic color math (blending, mixing, interpolation)
  • Working with canvas, WebGL, or image processing
  • Interfacing with APIs that expect channel values
  • Debugging at the pixel level

Use HSL when:

  • Quickly exploring color options in code
  • Building simple themes with hue rotation
  • Teaching color concepts to beginners
  • Working on projects without strict perceptual requirements

Use OKLCH when:

  • Building design system color scales
  • Generating palettes that need visual consistency
  • Making accessibility-informed color decisions
  • Working with wide-gamut displays (Display P3)
  • Creating CSS custom properties for theming

Converting Between Formats

In practice, you'll often need to move between formats. A designer sends you a HEX code, you need to generate lightness variants in OKLCH, and you store the final values as design tokens in HEX.

The math behind these conversions isn't trivial — especially OKLCH, which requires matrix transforms through linear sRGB and Oklab. Rather than implementing conversion functions yourself, use a reliable tool.

PixHue's Color Converter supports all four formats (plus LAB, Display P3, CMYK, and more). Paste any color value and instantly see the equivalent in every supported format. You can also use the Color Picker to visually explore how colors map across different spaces.

Beyond sRGB: Wide Gamut Colors

One reason OKLCH is gaining momentum is wide gamut support. Modern displays (particularly Apple devices, high-end monitors, and recent Android phones) support the Display P3 color space, which can render approximately 25% more colors than sRGB.

With OKLCH, you can define colors that take advantage of this expanded gamut:

/* A vivid green that's more saturated than anything sRGB can display */
.highlight {
  background: oklch(0.75 0.3 145);
}

If the user's display supports P3, they'll see the full vivid green. On sRGB displays, the browser gracefully clips to the nearest displayable color.

If you're interested in how color extraction works with these wider gamuts, our guide on how to pick colors from images covers the practical workflow.

Conclusion

There's no single "best" color format — each serves a purpose:

  • HEX is your storage and communication format
  • RGB is your computation format
  • HSL is your quick-exploration format
  • OKLCH is your professional-precision format

For modern web projects, the trend is clear: work in OKLCH for color decisions and palette generation, export to HEX for storage and legacy compatibility. This gives you the perceptual accuracy of OKLCH during the design process with the universal compatibility of HEX in your final deliverables.

Start exploring these formats side by side using PixHue's Color Converter, and visit pixhue.com to access the full suite of color workflow tools designed for professionals.