Colors Encyclopedia

Named color

Blue

Blue color #0000FF: RGB 0, 0, 255 and HSL 240°, 100%, 50%. Explore its cool blue profile, contrast, CSS, palettes and harmonies.

#0000FF blue cool vibrant
HEX #0000FF
RGB rgb(0, 0, 255)
HSL hsl(240 100% 50%)
CMYK cmyk(100, 100, 0, 0)
Luminance 0.0722
Contrast Black 2.44:1White 8.59:1

Use this color

Create with Blue

Open a professional color tool with #0000FF already applied. Each configuration stays canonical to the tool and can be adjusted or shared.

All color tools
Generate palette & CSS variablesCreate 50–950 tokens and export CSS, SCSS, JSON, or Tailwind.Open configured tool →Open in Gradient StudioStart with Blue and its complementary color.Open configured tool →Mix this colorBlend it with a complementary color and copy color-mix() CSS.Open configured tool →Check contrastOpen the strongest black or white background pairing.Open configured tool →Accessible combinationsReview AA and AAA text options, alternatives, warnings, and UI guidance.Open configured tool →Create glass surfaceUse this color as the tint for a translucent UI panel.Open configured tool →

CSS Utilities

--color-blue: #0000FF;
.bg-blue { background-color: #0000FF; }
.text-blue { color: #0000FF; }
Open CSS utility pageReusable variables, classes, examples, and implementation notes

Color meaning and use

About Blue Color

Blue uses HEX #0000FF, RGB 0, 0, 255, and HSL 240°, 100%, 50%. The dataset classifies it in the blue family with cool temperature and vibrant visual character.

No separate named-color neighbor is recorded for this entry. Its relative luminance is 0.0722; black contrast is 2.44:1 and white contrast is 8.59:1, making white the stronger of those two standard foreground choices.

WCAG Accessibility

Contrast checks for Blue against black and white text.

Black text2.44:1AA Fail
White text8.59:1AA Pass
AA text options#FFFFFF, #F5F5F5
AAA text options#FFFFFF, #F5F5F5
Open WCAG pageDetailed contrast notes, warnings, alternatives, and UI examples

Downloadable color reference infographic

Blue Color Reference Infographic

Save a high-resolution infographic of Blue, including its color values, coordinated palette, and black and white text contrast.

1200 × 800
Blue color reference infographic showing #0000FF, RGB and HSL values, a coordinated palette, and black and white text contrast.
Blue color reference infographic generated from the verified Colors Encyclopedia dataset.
Download WebPDownload SVGOpen full size

Color Harmonies

Yellow#FFFF00#007FFF#007FFF#7F00FF#7F00FFRed#FF0000Lime#00FF00
Open full Blue harmony pageComplementary, analogous, triadic, tetradic, split, and monochromatic sets

Variants

#5C5CFF#5C5CFF#0000A3#0000A3Blue#0000FF#1C1CE3#1C1CE3#8989F5#8989F5#2929FF#2929FF

Pairings

White#FFFFFFYellow#FFFF00#007FFF#007FFF#7F00FF#7F00FFMatte Black#1A1A1AWhite Smoke#F5F5F5

Machine-readable data

Machine-Readable Color Data (JSON)

Perfect for CSS, design systems, automation, and AI ingestion.

AI-Ready Dataset v1.0.0
Luminance0.0722
Black text2.44:1AA Fail
White text8.59:1AA Pass
hexCanonical HEX value
rgbRed, green, blue channels
hslHue, saturation, lightness
cmykApproximate print conversion
wcagAA and AAA contrast options
harmoniesMathematical harmony sets
variantsGenerated tone variants
nearestColorsKnowledge graph neighbors
Download JSON Open API
Structured sections
Color systems
{
  "hex": "#0000FF",
  "rgb": [
    0,
    0,
    255
  ],
  "hsl": [
    240,
    100,
    50
  ],
  "cmyk": [
    100,
    100,
    0,
    0
  ],
  "luminance": 0.0722,
  "contrast": {
    "black": 2.44,
    "white": 8.59
  }
}
WCAG
{
  "AA": [
    "#FFFFFF",
    "#F5F5F5"
  ],
  "AAA": [
    "#FFFFFF",
    "#F5F5F5"
  ]
}
Harmonies
{
  "complementary": "#FFFF00",
  "analogous": [
    "#007FFF",
    "#7F00FF"
  ],
  "triadic": [
    "#FF0000",
    "#00FF00"
  ],
  "tetradic": [
    "#FF0080",
    "#FFFF00",
    "#00FF80"
  ],
  "splitComplementary": [
    "#FF8000",
    "#80FF00"
  ],
  "monochromatic": [
    "#5C5CFF",
    "#0000FF",
    "#0000A3"
  ]
}
Variants
{
  "light": "#5C5CFF",
  "dark": "#0000A3",
  "saturated": "#0000FF",
  "desaturated": "#1C1CE3",
  "pastel": "#8989F5",
  "neon": "#2929FF"
}
Pairings
{
  "best": [
    "#FFFFFF",
    "#FFFF00",
    "#007FFF",
    "#7F00FF"
  ],
  "avoid": [
    "#1C1CE3",
    "#5C5CFF"
  ],
  "neutral": [
    "#1A1A1A",
    "#F5F5F5",
    "#E8E8E4"
  ],
  "highContrast": [
    "#FFFFFF"
  ],
  "lowContrast": [
    "#5C5CFF",
    "#1C1CE3"
  ]
}
Knowledge graph
{
  "nearestColors": [
    "medium-blue",
    "han-purple",
    "neon-blue",
    "zaffre",
    "persian-blue"
  ],
  "generatedPalettes": [
    "blue"
  ],
  "generatedComparisons": [
    "blue-vs-han-purple",
    "blue-vs-medium-blue"
  ],
  "relatedFamilies": [
    "/colors/by-family/blue",
    "/colors/by-temperature/cool",
    "/colors/by-tone/vibrant"
  ],
  "relatedTools": [
    "/harmonies/blue",
    "/wcag/blue",
    "/css/colors/blue",
    "/hex/0000ff",
    "/tools/css-gradient-generator",
    "/tools/color-palette-generator",
    "/tools/css-color-mixer",
    "/tools/contrast-checker"
  ],
  "semanticRelations": {
    "broader": [
      "/colors/by-family/blue",
      "/colors/by-temperature/cool",
      "/colors/by-tone/vibrant"
    ],
    "narrower": [
      "/palettes/blue"
    ],
    "related": [
      "/colors/medium-blue",
      "/colors/han-purple",
      "/colors/neon-blue",
      "/colors/zaffre",
      "/colors/persian-blue",
      "/compare/blue-vs-han-purple",
      "/compare/blue-vs-medium-blue",
      "/harmonies/blue",
      "/wcag/blue",
      "/css/colors/blue",
      "/hex/0000ff",
      "/tools/css-gradient-generator",
      "/tools/color-palette-generator",
      "/tools/css-color-mixer",
      "/tools/contrast-checker"
    ]
  }
}
Full JSON dataset 
{
  "slug": "blue",
  "name": "Blue",
  "cssName": "blue",
  "hex": "#0000FF",
  "family": "blue",
  "temperature": "cool",
  "tone": [
    "vibrant"
  ],
  "uses": [
    "web design",
    "CSS color systems",
    "UI prototyping"
  ],
  "psychology": {
    "associations": [
      "context dependent"
    ],
    "contexts": [
      "web interfaces",
      "design systems",
      "technical color references"
    ],
    "avoidIn": [
      "claims that require brand or cultural specificity"
    ]
  },
  "aliases": [
    "blue"
  ],
  "sourceType": "standard",
  "confidence": "high",
  "sourceUrl": "https://www.w3.org/TR/css-color-4/#named-colors",
  "origin": {
    "type": "css",
    "notes": "Standard CSS named color."
  },
  "reviewStatus": "auto",
  "editorialNotes": "Generated from CSS named color data and computed color-system properties.",
  "tags": [
    "blue",
    "cool",
    "vibrant",
    "web-design",
    "css-color-systems",
    "ui-prototyping",
    "context-dependent"
  ],
  "popularity": 82,
  "rgb": [
    0,
    0,
    255
  ],
  "hsl": [
    240,
    100,
    50
  ],
  "cmyk": [
    100,
    100,
    0,
    0
  ],
  "luminance": 0.0722,
  "contrast": {
    "black": 2.44,
    "white": 8.59
  },
  "harmonies": {
    "complementary": "#FFFF00",
    "analogous": [
      "#007FFF",
      "#7F00FF"
    ],
    "triadic": [
      "#FF0000",
      "#00FF00"
    ],
    "tetradic": [
      "#FF0080",
      "#FFFF00",
      "#00FF80"
    ],
    "splitComplementary": [
      "#FF8000",
      "#80FF00"
    ],
    "monochromatic": [
      "#5C5CFF",
      "#0000FF",
      "#0000A3"
    ]
  },
  "variants": {
    "light": "#5C5CFF",
    "dark": "#0000A3",
    "saturated": "#0000FF",
    "desaturated": "#1C1CE3",
    "pastel": "#8989F5",
    "neon": "#2929FF"
  },
  "wcag": {
    "AA": [
      "#FFFFFF",
      "#F5F5F5"
    ],
    "AAA": [
      "#FFFFFF",
      "#F5F5F5"
    ]
  },
  "css": {
    "variable": "--color-blue: #0000FF;",
    "utility": ".bg-blue { background-color: #0000FF; }",
    "textUtility": ".text-blue { color: #0000FF; }"
  },
  "nearestColors": [
    "medium-blue",
    "han-purple",
    "neon-blue",
    "zaffre",
    "persian-blue"
  ],
  "generatedPalettes": [
    "blue"
  ],
  "generatedComparisons": [
    "blue-vs-han-purple",
    "blue-vs-medium-blue"
  ],
  "relatedFamilies": [
    "/colors/by-family/blue",
    "/colors/by-temperature/cool",
    "/colors/by-tone/vibrant"
  ],
  "relatedTools": [
    "/harmonies/blue",
    "/wcag/blue",
    "/css/colors/blue",
    "/hex/0000ff",
    "/tools/css-gradient-generator",
    "/tools/color-palette-generator",
    "/tools/css-color-mixer",
    "/tools/contrast-checker"
  ],
  "semanticRelations": {
    "broader": [
      "/colors/by-family/blue",
      "/colors/by-temperature/cool",
      "/colors/by-tone/vibrant"
    ],
    "narrower": [
      "/palettes/blue"
    ],
    "related": [
      "/colors/medium-blue",
      "/colors/han-purple",
      "/colors/neon-blue",
      "/colors/zaffre",
      "/colors/persian-blue",
      "/compare/blue-vs-han-purple",
      "/compare/blue-vs-medium-blue",
      "/harmonies/blue",
      "/wcag/blue",
      "/css/colors/blue",
      "/hex/0000ff",
      "/tools/css-gradient-generator",
      "/tools/color-palette-generator",
      "/tools/css-color-mixer",
      "/tools/contrast-checker"
    ]
  },
  "pairings": {
    "best": [
      "#FFFFFF",
      "#FFFF00",
      "#007FFF",
      "#7F00FF"
    ],
    "avoid": [
      "#1C1CE3",
      "#5C5CFF"
    ],
    "neutral": [
      "#1A1A1A",
      "#F5F5F5",
      "#E8E8E4"
    ],
    "highContrast": [
      "#FFFFFF"
    ],
    "lowContrast": [
      "#5C5CFF",
      "#1C1CE3"
    ]
  }
}
Dataset manifest Version 1.0.0 Build hash published in manifest Canonical page

Similar Colors

Medium Blue#0000CD
Han Purple#5218FA
Neon Blue#1F51FF
Zaffre#0014A8
Persian Blue#1C39BB

Related Color Guides

Blue color familyBrowse named blue colors and compare nearby swatches.Cool colorsExplore colors with cool temperature behavior.Vibrant colorsFind colors with vibrant visual character.Blue accessibilityCheck contrast and WCAG text options for #0000FF.Blue CSS utilitiesUse Blue in CSS variables and utility classes.#0000FF HEX atlasOpen the permanent HEX atlas record for conversions and variants.Blue paletteOpen the generated palette based on Blue.Blue harmoniesExplore complementary, analogous, triadic, and tetradic harmonies.