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blue · cool

#669dfb

a light, electric blue · cool · closest name: Cornflower Blue

Token name suggestion: Meadow Cobalt

RGB
102, 157, 251
HSL
218°, 95%, 69%
CMYK
59, 38, 0, 2
Luminance
0.3390

#669dfb is a light electric blue, 218° on the wheel and 96/100 on the cool side. Put black text on it (7.78:1). As text it scores 2.70:1 on white — use #1B6DF9 instead. Nearest name is Cornflower Blue, nearest Tailwind family is blue.

hsl(218 95% 69%)rgb(102 157 251)Base step 400AAA inkCool

At a glance

Every number on this page in one read: what #669dfb is made of, how bright it looks, and which way it leans.

Hex
#669dfb
Hue
218°
blue
Saturation
95%
electric
Lightness
69%
light
Brightness
98%
HSV value
Perceived
62%
weighted brightness
Luminance
0.3390
WCAG relative
Temperature
Cool
96/100 cool
Color family
Blue
Tone
Electric
Best ink
Black
7.78:1
Closest name
Cornflower Blue
ΔE2000 2.7
Chroma
53.1
LCH, 0–130ish
OKLCH L
0.700
perceptual lightness
Tailwind
blue
500 · ΔE 8.4
Web-safe
#6699FF
nearest of 216
Where it sits
Hue218° of 360°
Saturation95%
Lightness69%
Saturation × lightness field

Left edge is grey, right edge is full chroma; top is white, bottom is black. The dot is #669dfb.

Temperature
Warm ← → Cool96% cool

Reads cool. Warm and cool siblings keep the same lightness, so you can swap one in without redoing your contrast maths.

Luminance by channel
Red8%
Green71%
Blue21%

Green carries most of what the eye calls brightness — that is why WCAG weights it 0.7152.

Every format

HEX#669dfb
HEX (8-digit)#669dfbff
RGBrgb(102, 157, 251)
RGBArgba(102, 157, 251, 1)
HSLhsl(218, 95%, 69%)
HSV / HSBhsv(218, 59%, 98%)
HWBhwb(218 40% 2%)
CMYKcmyk(59%, 38%, 0%, 2%)
LABlab(64.9 9.6 -52.3)
LCHlch(64.9 53.1 280.4)
OKLCHoklch(0.700 0.150 260.5)
XYZ (D65)xyz(34.94, 33.90, 95.95)
Decimal6725115
Display P3color(display-p3 0.400 0.616 0.984)
Web-safe#6699FF

Copy-ready code

every platformclick to select
/* CSS */
color: #669dfb;
background-color: #669dfb;
/* CSS custom property */
--brand: #669dfb;
/* Tailwind (arbitrary) */
class="text-[#669dfb] bg-[#669dfb]"
/* SCSS */
$brand: #669dfb;
/* SwiftUI */
Color(red: 0.400, green: 0.616, blue: 0.984)
/* UIKit */
UIColor(red: 0.400, green: 0.616, blue: 0.984, alpha: 1)
/* Android XML */
<color name="brand">#669DFB</color>
/* Android Compose */
Color(0xFF669DFB)
/* Flutter */
Color(0xFF669DFB)
/* Python / OpenCV (BGR) */
(251, 157, 102)
/* Python / PIL (RGB) */
(102, 157, 251)
/* Java AWT */
new Color(102, 157, 251)
/* .NET */
Color.FromArgb(255, 102, 157, 251)
/* OpenGL / Unity (0–1) */
(0.4000f, 0.6157f, 0.9843f, 1f)
/* LaTeX */
\definecolor{brand}{RGB}{102,157,251}
modern cssclick to select
/* mix without leaving CSS */
background: color-mix(in oklab, #669dfb 85%, white);
border-color: color-mix(in oklab, #669dfb 40%, transparent);
/* theme-aware in one line */
color: light-dark(#03307C, #D3DDEE);
/* relative colour syntax */
--hover: hsl(from #669dfb h s calc(l - 7));

Design tokens

The same ramp in the four formats a team actually needs. Paste one and the whole palette lands with it.

css custom propertiesclick to select
:root {
  --brand-50: #F1F6FD;
  --brand-100: #E4EDFB;
  --brand-200: #C2D6FA;
  --brand-300: #92B9FC;
  --brand-400: #669dfb;
  --brand-500: #2473F9;
  --brand-600: #065CEF;
  --brand-700: #054DC7;
  --brand-800: #043D9F;
  --brand-900: #082F73;
  --brand-950: #051D48;
  --brand: #669dfb;
  --brand-ink: #000000;
  --brand-surface: #F4F7FA;
  --brand-border: #C0D0ED;
  --brand-hover: #4387FA;
  --brand-pressed: #2070F9;
}
@media (prefers-color-scheme: dark) {
  :root {
    --brand-surface: #141A24;
    --brand-ink: #D3DDEE;
  }
}
tailwind.config.jsclick to select
theme: {
  extend: {
    colors: {
      brand: {
        50: '#F1F6FD',
        100: '#E4EDFB',
        200: '#C2D6FA',
        300: '#92B9FC',
        400: '#669dfb',
        500: '#2473F9',
        600: '#065CEF',
        700: '#054DC7',
        800: '#043D9F',
        900: '#082F73',
        950: '#051D48',
        DEFAULT: '#669dfb',
      },
    },
  },
}
scss mapclick to select
$brand: (
  '50': #F1F6FD,
  '100': #E4EDFB,
  '200': #C2D6FA,
  '300': #92B9FC,
  '400': #669dfb,
  '500': #2473F9,
  '600': #065CEF,
  '700': #054DC7,
  '800': #043D9F,
  '900': #082F73,
  '950': #051D48,
);
$brand-base: #669dfb;
$brand-ink: #000000;

@function brand($step) { @return map-get($brand, $step); }
w3c design tokens (json)click to select
{
  "color": {
    "brand": {
      "50": { "$value": "#F1F6FD", "$type": "color" },
      "100": { "$value": "#E4EDFB", "$type": "color" },
      "200": { "$value": "#C2D6FA", "$type": "color" },
      "300": { "$value": "#92B9FC", "$type": "color" },
      "400": { "$value": "#669dfb", "$type": "color" },
      "500": { "$value": "#2473F9", "$type": "color" },
      "600": { "$value": "#065CEF", "$type": "color" },
      "700": { "$value": "#054DC7", "$type": "color" },
      "800": { "$value": "#043D9F", "$type": "color" },
      "900": { "$value": "#082F73", "$type": "color" },
      "950": { "$value": "#051D48", "$type": "color" }
    },
    "brandInk": { "$value": "#000000", "$type": "color" }
  }
}

Best text color

Only one of black and white can be right. This is the one, with the number that proves it.

Readable at a glance#000000 on #669dfb · 7.78:1
Use #000000AAA at every size.
Aa
12px
Aa
16px
Aa
24px
Aa
White text · 2.70:1
AA fail · AA large fail · AAA fail
Aa
Black text · 7.78:1 · recommended
AA pass · AA large pass · AAA pass
Reading the other direction: #669dfb as text scores 2.70:1 on white and 7.78:1 on black.
Best tinted ink on it, if plain black or white feels flat: #03307C at 4.53:1.

Make it accessible

A contrast checker tells you that you failed. This tells you what to ship instead — same hue, same saturation, lightness moved only as far as WCAG demands.

The quick fox
#1B6DF9 · 4.56:1
AA on white−15% L
#1B6DF9
The quick fox
#054DC8 · 7.24:1
AAA on white−29% L
#054DC8
The quick fox
#669dfb · 7.78:1
AA on blackalready passes
#669dfb
The quick fox
#669dfb · 7.78:1
AAA on blackalready passes
#669dfb

Large text — 24px regular or 18.66px bold and above — only needs 3:1, so #5793FB is enough for headings on white. Non-text elements such as icons, chart strokes and focus rings also sit at 3:1 under WCAG 2.2 (1.4.11).

Accessibility — WCAG contrast

Aa
#669dfb on white: 2.70:1
AA ✗ fail · AA-large · AAA
Aa
#669dfb on black: 7.78:1
AA ✓ pass · AA-large · AAA
Against the neutral ladder

Contrast is symmetric, so each row covers both directions: #669dfb as text on that neutral, and that neutral as text on #669dfb.

NeutralRatioBoth directions
White2.70:1AaAa
Slate 502.58:1AaAa
Slate 1002.46:1AaAa
Slate 2002.19:1AaAa
Slate 3001.82:1AaAa
Slate 4001.05:1AaAa
Slate 5001.76:1AaAa
Slate 6002.81:1AaAa
Slate 7003.84:1AaAa
Slate 8005.42:1AaAa
Slate 9006.61:1AaAa
Black7.78:1AaAa
Colour vision deficiency
true color
protanopia · #75A5FF
deuteranopia · #6197F9
tritanopia · #00B2C0

Roughly one man in twelve has some form of colour vision deficiency. If any of the three panels above is hard to tell apart from a neighbouring colour in your palette, add a shape, an icon or a label so the meaning does not rest on hue alone.

Color scale — 50 to 950

A Tailwind-shaped ramp built around this exact hex. #669dfb is pinned to step 400; the rest hold its hue and let saturation ease off at the extremes so the pale end never turns neon.

#F1F6FD
#E4EDFB
#C2D6FA
#92B9FC
#669dfb
#2473F9
#065CEF
#054DC7
#043D9F
#082F73
#051D48
Base = 400Lightest = 50 · #F1F6FDDarkest = 950 · #051D48Text step on white = 600
Perceptual ramp — OKLCH

The same eleven steps expressed in OKLCH, where equal lightness numbers actually look equally spaced. HSL ramps go muddy in the yellows and washed out in the blues; this one does not. Modern browsers render it natively — the hex ramp above is the fallback.

50100200300400500600700800900950
oklch tokensclick to select
:root {
  --brand-50: oklch(0.97 0.038 260.5);
  --brand-100: oklch(0.94 0.060 260.5);
  --brand-200: oklch(0.88 0.090 260.5);
  --brand-300: oklch(0.80 0.117 260.5);
  --brand-400: oklch(0.72 0.138 260.5);
  --brand-500: oklch(0.64 0.150 260.5);
  --brand-600: oklch(0.56 0.150 260.5);
  --brand-700: oklch(0.48 0.141 260.5);
  --brand-800: oklch(0.40 0.126 260.5);
  --brand-900: oklch(0.32 0.105 260.5);
  --brand-950: oklch(0.24 0.083 260.5);
}

Colors that work with #669dfb

Not a palette — a role sheet. Each swatch answers one question you will hit while building the component.

Text on it#000000
Black wins here
Surface#F4F7FA
Tinted page background
Border#C0D0ED
Hairlines and dividers
Muted text#4B689B
Captions on the surface
Accent#CB4E01
Second voice, not a rival
Dark variant#03307C
Hover, pressed, headers
Light variant#E6EFFE
Selected rows, tints
Dark surface#141A24
Dark-mode background
Hover#4387FA
One step down in lightness
Pressed#2070F9
Two steps down
Disabled#E4E7ED
Chroma pulled out
Focus ring#76A9FF
Offset from the fill so it reads
Light mode
Everything in its place

Surface, border, heading and body all derive from this one hue, so the screen stays coherent without a second palette.

Primary actionSecondaryBadge
Dark mode
Same hue, inverted

Lightness flips, hue holds. The accent stays the anchor in both themes.

Primary actionSecondaryAccent

In real components

The same eight roles, wired into the interface patterns you will actually build with them. Every state below is a computed value, not a mock-up.

Buttons and states
Save changesHoverPressedDisabled
OutlineSubtleLinkFocused
Form field
you@company.com

Focus ring uses the light variant so the field still reads as one shape.

Send me product updates
Notice
Your export is ready

The file stays available for seven days. Download it before it expires.

NewBetaDraft
Data
Storage used68%
Acme LtdActive
NorthwindTrial
GlobexActive

How to use #669dfb

Derived from its contrast, chroma and lightness — not from taste.

Works well for
  • Text and icons on dark surfaces
  • Primary buttons and calls to action
  • Focus rings, active and selected states
  • Card and section backgrounds
  • Brand accents, badges and data highlights
Use with care
  • Text of any size on white — fails WCAG AA
  • Full-page backgrounds — tiring over long sessions
  • White text placed on it
  • Pairing with a same-lightness hue — edges vibrate
Minimum size as text on white
Not as text
Safe as a fill behind white type
No — use #03307C
Safe as a 1px border on white
No — use #5793FB

Meaning and mood

What a colour in this family tends to signal, and how this particular chroma and lightness change the reading.

trustedcalmcompetentcorporate

The default of institutions for a reason: blue is read as stable and safe across nearly every culture that has been surveyed.

At this chroma the association is amplified — it will dominate anything placed beside it, so give it space and use it sparingly. The lightness keeps it airy and approachable.

Worth knowing

It is also the most crowded hue on the web. Distinctiveness has to come from your other choices.

Reads as
  • FormalityLow
  • EnergyHigh
  • Weight31/100
  • TemperatureCool
  • ApproachabilityReserved

Colour associations are cultural and vary by market. Treat these as a starting point for a conversation with your audience, not a finding about them.

Similar colors

One move away from this hex in each direction. Every swatch is its own page.

Color relationships

The wheel positions with their names attached, so you can grab the one you actually need.

Complementary#FBC466
Analogous left#66E7FB
Analogous right#7A66FB
Split-complement 1#FB7A66
Split-complement 2#E7FB66
Triadic 1#FB669D
Triadic 2#9DFB66
Tetradic#FB66E7
On the wheel
Base+30°−30°+120°+240°+180°218°

#669dfb sits at 218°. Every dot is a harmony position and links to its own page in the table alongside.

RGB percentages

Red40.0%
Green61.6%
Blue98.4%
R · 0–255
102
0x66
G · 0–255
157
0x9d
B · 0–255
251
0xfb

CMYK percentages

Cyan59.4%
Magenta37.5%
Yellow0.0%
Key (black)1.6%

Total ink coverage is 99%. Most commercial presses cap around 300% — above that, sheets stop drying properly.

Color previews

#669dfb text on a black background

contrast 7.78:1

Card sample

#669dfb text on a white background

contrast 2.70:1

Card sample

#669dfb on grey

2.46:1

#669dfb on its own surface

2.51:1

#669dfb on its dark surface

6.47:1

CSS3 live lab

Text font color

The quick brown fox

color: #669dfb;
Background color
Panel with #669dfb background
background-color: #669dfb;
Text shadow — hex

Glowing headline

text-shadow: 2px 2px 8px #669dfb;
Text shadow — RGB

Soft neon halo

text-shadow: 0 0 14px rgba(102, 157, 251, 0.45);
Div box shadow
Elevated card
box-shadow: 0 12px 32px -8px rgba(102, 157, 251, 0.45);
Border & gradient
Gradient panel
border: 3px solid #669dfb;
background: linear-gradient(135deg, #669dfb, #9266FB);
Gradient text

Gradient headline

background: linear-gradient(90deg, #669dfb, #B866FB);
-webkit-background-clip: text;
color: transparent;
Focus ring
Focused control
outline: 2px solid #669dfb;
outline-offset: 3px;
Underline & caret

Marked up text

text-decoration-color: #669dfb;
caret-color: #669dfb;
Left rule
Pull quote or callout
border-left: 4px solid #669dfb;
Ring + tint
Selected chip
background: #E6EFFE;
box-shadow: inset 0 0 0 2px #669dfb;
Conic badge
68%
background: conic-gradient(#669dfb 68%, #e2e8f0 0);

Transparency

What each alpha value actually composites to. The top row is #669dfb over white; the bottom row is the same alpha over a checkerboard, so you can see what survives on a photo or a video.

Bottom row of hexes is the flattened result over white — use those when a design tool refuses transparency, or when you need a solid fallback.

alpha in every syntaxclick to select
rgba(102, 157, 251, 0.5)
rgb(102 157 251 / 50%)
#669dfb80
hsl(218 95% 69% / 50%)
color-mix(in srgb, #669dfb 50%, transparent)
Alpha8-digit hexFlat on white
10%#669dfb1a#F0F5FF
20%#669dfb33#E0EBFE
40%#669dfb66#C2D8FD
60%#669dfb99#A3C4FD
80%#669dfbcc#85B1FC

Gradients from #669dfb

Six recipes, each built from this hex and shown with the exact CSS that produced it.

Elevation
Same hue, three lightnesses — safe anywhere
background: linear-gradient(135deg, #A2C3FD, #669dfb 45%, #03307C);
Duotone
A short hue run reads richer than a flat fill
background: linear-gradient(120deg, #669dfb, #8C48FA);
Complement sweep
Loud — keep it behind large type only
background: linear-gradient(90deg, #669dfb, #FBC466);
Spotlight
Hero panels and app headers
background: radial-gradient(120% 120% at 20% 0%, #BFD6FD 0%, #669dfb 45%, #03307C 100%);
Soft wash
Section backgrounds that stay readable
background: linear-gradient(180deg, #F4F7FA, #ffffff);
Mesh
Ambient background, no image weight
background: radial-gradient(60% 60% at 15% 20%, #98F7FC 0%, transparent 60%), radial-gradient(55% 55% at 85% 15%, #9E84FC 0%, transparent 60%), radial-gradient(70% 70% at 50% 95%, #03307C 0%, transparent 65%), #669dfb;

Monochromatic scale

Palettes built from #669dfb

Shades — darker

Tints — lighter

Tones — desaturated

Color harmonies

Nearest named colors

Ranked with CIEDE2000 across all 139 CSS keywords. Under ΔE 2 the eye stops telling them apart; over ΔE 10 they are plainly different colors.

#669dfb in the real world

Where a color in this family tends to land, and the interface roles it is usually asked to play.

Industries
TechnologyFinanceHealthcareEnterprise SaaS
Common UI roles
SurfacesBadgesHighlightsEmpty states
Print note

Sits outside most CMYK gamuts — expect a duller press result, or specify a spot ink.

On screens

Holds up across typical panel gamma. Still worth checking on an uncalibrated laptop, where mid-tones shift most.

In dark mode

Usable as-is on a dark surface at 7.78:1.

Explore nearby colors

Small, deliberate steps away from this hex — useful when you are hunting for the version of a colour that finally feels right.

#669dfb, answered

What color is #669dfb?

#669dfb is a light electric blue, closest to Cornflower Blue (ΔE2000 2.7). It sits at 218° on the hue wheel with 95% saturation and 69% lightness, which reads as cool.

What is the RGB value of #669dfb?

rgb(102, 157, 251) — 102 red, 157 green and 251 blue out of 255, or 40% / 61.6% / 98.4% by channel.

What is #669dfb in HSL and HSV?

hsl(218, 95%, 69%) and hsv(218, 59%, 98%). HSL is what CSS takes; HSV is what your design tool's picker shows, which is why the saturation numbers rarely match.

Is #669dfb a light or a dark color?

It is a mid-tone. Relative luminance is 0.3390 and perceived brightness is 62%, so black text on it reaches 7.78:1.

Should I use black or white text on #669dfb?

Black. It scores 7.78:1 against #669dfb, versus 2.70:1 for white — AAA at any size.

Is #669dfb accessible on a white background?

#669dfb on white scores 2.70:1, which fails WCAG AA at every size. Darken it to #1B6DF9 to reach 4.5:1, or #054DC8 for 7:1.

What is the complementary color of #669dfb?

#FBC466 sits directly opposite on the wheel. Softer options are the split-complements #FB7A66 and #E7FB66, which give the same contrast with far less vibration.

What colors go well with #669dfb?

For interface work: #F4F7FA as the surface, #C0D0ED for borders, #4B689B for secondary text, #CB4E01 as an accent and #03307C for hover and pressed states. For a palette, the analogous pair #66E7FB and #7A66FB stays calm, while #FBC466 is the loudest partner.

What is #669dfb in CMYK for printing?

cmyk(59%, 38%, 0%, 2%). This is a screen-to-ink approximation — a color this saturated sits outside most CMYK gamuts and will print duller than it looks here.

Is #669dfb warm or cool?

Cool — it scores 96 on a scale where 0 is the warmest orange and 100 the coolest azure. Nudged warmer it becomes #6666FB; nudged cooler, #4B97FC.

Which Tailwind color is closest to #669dfb?

The blue family — its 500 step is #3b82f6, ΔE2000 8.4 away. That is a visible difference, so define #669dfb as a custom token rather than reaching for the built-in.

How do I use #669dfb in Tailwind CSS?

Inline it as an arbitrary value with bg-[#669dfb] or text-[#669dfb], or register the whole ramp under theme.extend.colors.brand so you get bg-brand-500 and friends. The generated 50–950 scale on this page is ready to paste into your config.

What is #669dfb with 50% opacity?

rgba(102, 157, 251, 0.5), or #669dfb80 in eight-digit hex. Over white that composites to #B3CEFD; over black, #334F7E.

Is #669dfb a web-safe color?

No. The nearest web-safe colour is #6699FF, ΔE2000 1.5 away. The palette only matters for legacy displays and some email clients now.

What does the color #669dfb mean?

As a blue, it reads trusted, calm, competent. The default of institutions for a reason: blue is read as stable and safe across nearly every culture that has been surveyed. At this chroma the effect is amplified — it will dominate whatever sits beside it.

What gradient works with #669dfb?

The safest is same-hue elevation: linear-gradient(135deg, #A2C3FD, #669dfb 45%, #03307C). For more colour, a short hue run to #8C48FA keeps it rich without turning muddy.

Work with #669dfb in the Color Lab

Every tool opens with this colour already loaded.

Every value on this page is computed from #669dfb at request time — conversions, contrast ratios and ΔE distances are calculated, never looked up.