CSS named colour

Blue

#0000ff

A CSS named colour: blue is valid anywhere a colour is expected.

RGB: rgb(0 0 255)
HSL: 240°, 100%, 50%
OKLCh: 45.2% 0.313 264.1

Blue in every format

Web & CSSThe everyday formats for stylesheets and design tools.

Hex	`#0000ff`
RGB	`rgb(0 0 255)`
RGB legacy	`rgb(0, 0, 255)`
RGB percent	`rgb(0% 0% 100%)`
HSL	`hsl(240 100% 50%)`
HSL legacy	`hsl(240, 100%, 50%)`
HSV / HSB	`hsv(240, 100%, 100%)`
HWB	`hwb(240 0% 0%)`
Nearest name	`blue`
CMYK	`cmyk(100%, 100%, 0%, 0%)`Naive conversion. Real print work needs an ICC profile.

Perceptual & wide gamutModern CSS colour spaces for uniform scales and P3 displays.

OKLCh	`oklch(45.201% 0.31321 264.052)`Modern CSS colour space for even palettes — better than HSL when building scales.
OKLab	`oklab(45.201% -0.03246 -0.31153)`
CIE LCh	`lch(29.568% 131.201 301.364)`
CIE Lab	`lab(29.568% 68.287 -112.03)`
Display P3	`color(display-p3 0 0 0.9596)`
Rec. 2020	`color(rec2020 0.1684 0.0511 0.9468)`
srgb-linear	`color(srgb-linear 0 0 1)`Light-linear sRGB — the same numbers a shader wants for maths.
CIE XYZ (D65)	`color(xyz-d65 0.1805 0.0722 0.9505)`

ShadersGLSL, HLSL and WGSL vectors in both encoded and linear form.

GLSL vec3 — sRGB	`vec3(0.0, 0.0, 1.0)`Encoded values. Use when writing straight to the framebuffer.
GLSL vec3 — linear	`vec3(0.0, 0.0, 1.0)`Light-linear values. Use for lighting, blending and mixing.
GLSL vec4 — sRGB	`vec4(0.0, 0.0, 1.0, 1.0)`
GLSL vec4 — linear	`vec4(0.0, 0.0, 1.0, 1.0)`
GLSL ivec3	`ivec3(0, 0, 255)`
HLSL float3 — sRGB	`float3(0.0, 0.0, 1.0)`
HLSL float3 — linear	`float3(0.0, 0.0, 1.0)`
HLSL float4 — sRGB	`float4(0.0, 0.0, 1.0, 1.0)`
HLSL half4 — sRGB	`half4(0.0, 0.0, 1.0, 1.0)`
WGSL vec3f — sRGB	`vec3f(0.0, 0.0, 1.0)`
WGSL vec4f — sRGB	`vec4f(0.0, 0.0, 1.0, 1.0)`
WGSL vec3<f32> — linear	`vec3<f32>(0.0, 0.0, 1.0)`

Engines & appsConstructors for Unity, Unreal, Godot, Flutter, SwiftUI and Android.

Unity Color	`new Color(0.0f, 0.0f, 1.0f, 1.0f)`Color for everyday scripting (0–1). Color32 when you need whole numbers from 0 to 255.
Unity Color32	`new Color32(0, 0, 255, 255)`
Unreal FLinearColor	`FLinearColor(0.0f, 0.0f, 1.0f, 1.0f)`FLinearColor for materials and lighting. FColor when you need whole numbers from 0 to 255.
Unreal FColor	`FColor(0, 0, 255, 255)`Whole numbers from 0 to 255 — use when an API asks for FColor, not FLinearColor.
Godot Color	`Color(0, 0, 1, 1)`
Flutter Color	`Color(0xFF0000FF)`Packed ARGB, so alpha comes first.
Android Color	`Color.rgb(0, 0, 255)`
SwiftUI Color	`Color(red: 0, green: 0, blue: 1)`
UIKit UIColor	`UIColor(red: 0, green: 0, blue: 1, alpha: 1)`

Raw valuesPacked integers and plain arrays.

0x hex	`0x0000FF`
0x hex (ARGB)	`0xFF0000FF`
Array 0–1	`[0, 0, 1]`
Array 0–255	`[0, 0, 255]`
Decimal integer	`255`

Contrast and accessibility

WCAG 2 ratios are what audits and legislation reference. APCA is shown alongside because WCAG 2 is known to misjudge mid-tone backgrounds, and it is the basis of the WCAG 3 draft.

Pairing	WCAG 2 ratio	Level	APCA	Suitable for
Blue on white	8.59:1	AAA	Lc 86	Body text, 18px and up
Blue on black	2.44:1	Fail	Lc 16	Not usable for text

Blue text on a white background

Blue text on a black background

White text on Blue

Black text on Blue

Tonal scale

Hue held fixed while lightness walks OKLCh, ready to use as a design system ramp.

50#edf8ff
100#deeeff
200#c4ddff
300#a2c5ff
400#75a5ff
500#447fff
600#1656ff
700#002ef8
800#000fd4
900#0200b5
950#020076

Tints and shades

Mixed perceptually toward white and black, so the steps feel evenly spaced.

Tint 1#1957ff
Tint 2#4780ff
Tint 3#74a3ff
Tint 4#a1c3ff
Tint 5#cfe1ff
Shade 1#0000c8
Shade 2#000094
Shade 3#000063
Shade 4#000036
Shade 5#00000f

Colours that work with Blue

Complementary, triadic and analogous partners, rotated in OKLCh so they keep the same apparent brightness.

#734f00
#aa0011
#006c00
#005e8d
#6900d9

Closest CSS names

blueexact match
mediumblueΔEok 0.083
royalblueΔEok 0.165
slateblueΔEok 0.190
darkblueΔEok 0.200
darkslateblueΔEok 0.206