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cyan · cool

#129eb9

a dark, electric cyan · cool · closest name: Cadet Blue

Token name suggestion: Shadow Reef

RGB
18, 158, 185
HSL
190°, 82%, 40%
CMYK
90, 15, 0, 28
Luminance
0.2809

#129eb9 is a dark electric cyan, 190° on the wheel and 92/100 on the cool side. Put black text on it (6.62:1). As text it scores 3.17:1 on white — large text only. Nearest name is Cadet Blue, nearest Tailwind family is cyan.

hsl(190 82% 40%)rgb(18 158 185)Base step 700AA inkCool

At a glance

Every number on this page in one read: what #129eb9 is made of, how bright it looks, and which way it leans.

Hex
#129eb9
Hue
190°
cyan
Saturation
82%
electric
Lightness
40%
dark
Brightness
73%
HSV value
Perceived
54%
weighted brightness
Luminance
0.2809
WCAG relative
Temperature
Cool
92/100 cool
Color family
Cyan
Tone
Electric
Best ink
Black
6.62:1
Closest name
Cadet Blue
ΔE2000 9.2
Chroma
33.6
LCH, 0–130ish
OKLCH L
0.645
perceptual lightness
Tailwind
cyan
500 · ΔE 7.1
Web-safe
#0099CC
nearest of 216
Where it sits
Hue190° of 360°
Saturation82%
Lightness40%
Saturation × lightness field

Left edge is grey, right edge is full chroma; top is white, bottom is black. The dot is #129eb9.

Temperature
Warm ← → Cool92% 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
Red0%
Green87%
Blue12%

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

Every format

HEX#129eb9
HEX (8-digit)#129eb9ff
RGBrgb(18, 158, 185)
RGBArgba(18, 158, 185, 1)
HSLhsl(190, 82%, 40%)
HSV / HSBhsv(190, 90%, 73%)
HWBhwb(190 7% 27%)
CMYKcmyk(90%, 15%, 0%, 28%)
LABlab(60.0 -24.1 -23.5)
LCHlch(60.0 33.6 224.4)
OKLCHoklch(0.645 0.112 216.1)
XYZ (D65)xyz(21.23, 28.08, 50.19)
Decimal1220281
Display P3color(display-p3 0.071 0.620 0.725)
Web-safe#0099CC

Copy-ready code

every platformclick to select
/* CSS */
color: #129eb9;
background-color: #129eb9;
/* CSS custom property */
--brand: #129eb9;
/* Tailwind (arbitrary) */
class="text-[#129eb9] bg-[#129eb9]"
/* SCSS */
$brand: #129eb9;
/* SwiftUI */
Color(red: 0.071, green: 0.620, blue: 0.725)
/* UIKit */
UIColor(red: 0.071, green: 0.620, blue: 0.725, alpha: 1)
/* Android XML */
<color name="brand">#129EB9</color>
/* Android Compose */
Color(0xFF129EB9)
/* Flutter */
Color(0xFF129EB9)
/* Python / OpenCV (BGR) */
(185, 158, 18)
/* Python / PIL (RGB) */
(18, 158, 185)
/* Java AWT */
new Color(18, 158, 185)
/* .NET */
Color.FromArgb(255, 18, 158, 185)
/* OpenGL / Unity (0–1) */
(0.0706f, 0.6196f, 0.7255f, 1f)
/* LaTeX */
\definecolor{brand}{RGB}{18,158,185}
modern cssclick to select
/* mix without leaving CSS */
background: color-mix(in oklab, #129eb9 85%, white);
border-color: color-mix(in oklab, #129eb9 40%, transparent);
/* theme-aware in one line */
color: light-dark(#0B6374, #D3EAEE);
/* relative colour syntax */
--hover: hsl(from #129eb9 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: #F2FBFC;
  --brand-100: #E6F6FA;
  --brand-200: #C6EEF6;
  --brand-300: #99E6F5;
  --brand-400: #66DAF0;
  --brand-500: #32CDEB;
  --brand-600: #16BFDF;
  --brand-700: #129eb9;
  --brand-800: #0E7F95;
  --brand-900: #0F5D6C;
  --brand-950: #093A43;
  --brand: #129eb9;
  --brand-ink: #000000;
  --brand-surface: #F4F9FA;
  --brand-border: #C0E5ED;
  --brand-hover: #0F8298;
  --brand-pressed: #0C6678;
}
@media (prefers-color-scheme: dark) {
  :root {
    --brand-surface: #142224;
    --brand-ink: #D3EAEE;
  }
}
tailwind.config.jsclick to select
theme: {
  extend: {
    colors: {
      brand: {
        50: '#F2FBFC',
        100: '#E6F6FA',
        200: '#C6EEF6',
        300: '#99E6F5',
        400: '#66DAF0',
        500: '#32CDEB',
        600: '#16BFDF',
        700: '#129eb9',
        800: '#0E7F95',
        900: '#0F5D6C',
        950: '#093A43',
        DEFAULT: '#129eb9',
      },
    },
  },
}
scss mapclick to select
$brand: (
  '50': #F2FBFC,
  '100': #E6F6FA,
  '200': #C6EEF6,
  '300': #99E6F5,
  '400': #66DAF0,
  '500': #32CDEB,
  '600': #16BFDF,
  '700': #129eb9,
  '800': #0E7F95,
  '900': #0F5D6C,
  '950': #093A43,
);
$brand-base: #129eb9;
$brand-ink: #000000;

@function brand($step) { @return map-get($brand, $step); }
w3c design tokens (json)click to select
{
  "color": {
    "brand": {
      "50": { "$value": "#F2FBFC", "$type": "color" },
      "100": { "$value": "#E6F6FA", "$type": "color" },
      "200": { "$value": "#C6EEF6", "$type": "color" },
      "300": { "$value": "#99E6F5", "$type": "color" },
      "400": { "$value": "#66DAF0", "$type": "color" },
      "500": { "$value": "#32CDEB", "$type": "color" },
      "600": { "$value": "#16BFDF", "$type": "color" },
      "700": { "$value": "#129eb9", "$type": "color" },
      "800": { "$value": "#0E7F95", "$type": "color" },
      "900": { "$value": "#0F5D6C", "$type": "color" },
      "950": { "$value": "#093A43", "$type": "color" }
    },
    "brandInk": { "$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 #129eb9 · 6.62:1
Use #000000AA at every size, AAA for large text only.
Aa
12px
Aa
16px
Aa
24px
Aa
White text · 3.17:1
AA fail · AA large pass · AAA fail
Aa
Black text · 6.62:1 · recommended
AA pass · AA large pass · AAA fail
Reading the other direction: #129eb9 as text scores 3.17:1 on white and 6.62:1 on black.
Best tinted ink on it, if plain black or white feels flat: #0B6374 at 2.17:1.

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
#0F8298 · 4.50:1
AA on white−7% L
#0F8298
The quick fox
#0B5E6F · 7.38:1
AAA on white−16% L
#0B5E6F
The quick fox
#129eb9 · 6.62:1
AA on blackalready passes
#129eb9
The quick fox
#13A6C2 · 7.26:1
AAA on black+2% L
#13A6C2

Large text — 24px regular or 18.66px bold and above — only needs 3:1, so #129EB9 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
#129eb9 on white: 3.17:1
AA ✗ fail · AA-large · AAA
Aa
#129eb9 on black: 6.62:1
AA ✓ pass · AA-large · AAA
Against the neutral ladder

Contrast is symmetric, so each row covers both directions: #129eb9 as text on that neutral, and that neutral as text on #129eb9.

NeutralRatioBoth directions
White3.17:1AaAa
Slate 503.03:1AaAa
Slate 1002.90:1AaAa
Slate 2002.57:1AaAa
Slate 3002.14:1AaAa
Slate 4001.24:1AaAa
Slate 5001.50:1AaAa
Slate 6002.39:1AaAa
Slate 7003.26:1AaAa
Slate 8004.61:1AaAa
Slate 9005.63:1AaAa
Black6.62:1AaAa
Colour vision deficiency
true color
protanopia · #8C99BA
deuteranopia · #778AB9
tritanopia · #00A8A6

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. #129eb9 is pinned to step 700; the rest hold its hue and let saturation ease off at the extremes so the pale end never turns neon.

#F2FBFC
#E6F6FA
#C6EEF6
#99E6F5
#66DAF0
#32CDEB
#16BFDF
#129eb9
#0E7F95
#0F5D6C
#093A43
Base = 700Lightest = 50 · #F2FBFCDarkest = 950 · #093A43Text step on white = 800
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 0.028 216.1);
  --brand-100: oklch(0.94 0.045 216.1);
  --brand-200: oklch(0.88 0.067 216.1);
  --brand-300: oklch(0.80 0.087 216.1);
  --brand-400: oklch(0.72 0.103 216.1);
  --brand-500: oklch(0.64 0.112 216.1);
  --brand-600: oklch(0.56 0.112 216.1);
  --brand-700: oklch(0.48 0.105 216.1);
  --brand-800: oklch(0.40 0.094 216.1);
  --brand-900: oklch(0.32 0.078 216.1);
  --brand-950: oklch(0.24 0.061 216.1);
}

Colors that work with #129eb9

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#F4F9FA
Tinted page background
Border#C0E5ED
Hairlines and dividers
Muted text#4B8E9B
Captions on the surface
Accent#BD0E1D
Second voice, not a rival
Dark variant#0B6374
Hover, pressed, headers
Light variant#E8F9FD
Selected rows, tints
Dark surface#142224
Dark-mode background
Hover#0F8298
One step down in lightness
Pressed#0C6678
Two steps down
Disabled#88ACB3
Chroma pulled out
Focus ring#09B5D7
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 #129eb9

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

Works well for
  • Headings from 24px up on white
  • Text and icons on dark surfaces
  • Primary buttons and calls to action
  • Focus rings, active and selected states
  • Headers, footers and dark-mode surfaces
  • Brand accents, badges and data highlights
Use with care
  • Small text on white — under 4.5:1
  • Full-page backgrounds — tiring over long sessions
  • Black text placed on it
  • Thin strokes and 1px borders — they disappear on light UI
  • Pairing with a same-lightness hue — edges vibrate
Minimum size as text on white
24px / 18.66px bold
Safe as a fill behind white type
No — use #0B6374
Safe as a 1px border on white
Yes

Meaning and mood

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

cleantechnicalfreshclinical

Cyan reads as water, air and infrastructure: cool, hygienic, engineered.

At this chroma the association is amplified — it will dominate anything placed beside it, so give it space and use it sparingly. The low lightness adds weight and formality.

Worth knowing

At high lightness it disappears into white surfaces and thin strokes vanish entirely.

Reads as
  • FormalityHigh
  • EnergyHigh
  • Weight60/100
  • 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#B92D12
Analogous left#12B980
Analogous right#124AB9
Split-complement 1#B9124A
Split-complement 2#B98012
Triadic 1#B9129E
Triadic 2#9EB912
Tetradic#8012B9
On the wheel
Base+30°−30°+120°+240°+180°190°

#129eb9 sits at 190°. Every dot is a harmony position and links to its own page in the table alongside.

RGB percentages

Red7.1%
Green62.0%
Blue72.5%
R · 0–255
18
0x12
G · 0–255
158
0x9e
B · 0–255
185
0xb9

CMYK percentages

Cyan90.3%
Magenta14.6%
Yellow0.0%
Key (black)27.5%

Total ink coverage is 132%. Most commercial presses cap around 300% — above that, sheets stop drying properly.

Color previews

#129eb9 text on a black background

contrast 6.62:1

Card sample

#129eb9 text on a white background

contrast 3.17:1

Card sample

#129eb9 on grey

2.90:1

#129eb9 on its own surface

2.99:1

#129eb9 on its dark surface

5.15:1

CSS3 live lab

Text font color

The quick brown fox

color: #129eb9;
Background color
Panel with #129eb9 background
background-color: #129eb9;
Text shadow — hex

Glowing headline

text-shadow: 2px 2px 8px #129eb9;
Text shadow — RGB

Soft neon halo

text-shadow: 0 0 14px rgba(18, 158, 185, 0.45);
Div box shadow
Elevated card
box-shadow: 0 12px 32px -8px rgba(18, 158, 185, 0.45);
Border & gradient
Gradient panel
border: 3px solid #129eb9;
background: linear-gradient(135deg, #129eb9, #122FB9);
Gradient text

Gradient headline

background: linear-gradient(90deg, #129eb9, #1F12B9);
-webkit-background-clip: text;
color: transparent;
Focus ring
Focused control
outline: 2px solid #129eb9;
outline-offset: 3px;
Underline & caret

Marked up text

text-decoration-color: #129eb9;
caret-color: #129eb9;
Left rule
Pull quote or callout
border-left: 4px solid #129eb9;
Ring + tint
Selected chip
background: #E8F9FD;
box-shadow: inset 0 0 0 2px #129eb9;
Conic badge
68%
background: conic-gradient(#129eb9 68%, #e2e8f0 0);

Transparency

What each alpha value actually composites to. The top row is #129eb9 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(18, 158, 185, 0.5)
rgb(18 158 185 / 50%)
#129eb980
hsl(190 82% 40% / 50%)
color-mix(in srgb, #129eb9 50%, transparent)
Alpha8-digit hexFlat on white
10%#129eb91a#E7F5F8
20%#129eb933#D0ECF1
40%#129eb966#A0D8E3
60%#129eb999#71C5D5
80%#129eb9cc#41B1C7

Gradients from #129eb9

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, #1FC9E9, #129eb9 45%, #0B6374);
Duotone
A short hue run reads richer than a flat fill
background: linear-gradient(120deg, #129eb9, #0F1C9D);
Complement sweep
Loud — keep it behind large type only
background: linear-gradient(90deg, #129eb9, #B92D12);
Spotlight
Hero panels and app headers
background: radial-gradient(120% 120% at 20% 0%, #3BCFEC 0%, #129eb9 45%, #0B6374 100%);
Soft wash
Section backgrounds that stay readable
background: linear-gradient(180deg, #F4F9FA, #ffffff);
Mesh
Ambient background, no image weight
background: radial-gradient(60% 60% at 15% 20%, #16E88F 0%, transparent 60%), radial-gradient(55% 55% at 85% 15%, #1546D5 0%, transparent 60%), radial-gradient(70% 70% at 50% 95%, #0B6374 0%, transparent 65%), #129eb9;

Monochromatic scale

Palettes built from #129eb9

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.

#129eb9 in the real world

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

Industries
TechnologyTravelHealthcareMedia
Common UI roles
ButtonsLinksFocus statesCharts
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 6.62:1.

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.

#129eb9, answered

What color is #129eb9?

#129eb9 is a dark electric cyan, closest to Cadet Blue (ΔE2000 9.2). It sits at 190° on the hue wheel with 82% saturation and 40% lightness, which reads as cool.

What is the RGB value of #129eb9?

rgb(18, 158, 185) — 18 red, 158 green and 185 blue out of 255, or 7.1% / 62% / 72.5% by channel.

What is #129eb9 in HSL and HSV?

hsl(190, 82%, 40%) and hsv(190, 90%, 73%). HSL is what CSS takes; HSV is what your design tool's picker shows, which is why the saturation numbers rarely match.

Is #129eb9 a light or a dark color?

It is a mid-tone. Relative luminance is 0.2809 and perceived brightness is 54%, so black text on it reaches 6.62:1.

Should I use black or white text on #129eb9?

Black. It scores 6.62:1 against #129eb9, versus 3.17:1 for white — AA at any size.

Is #129eb9 accessible on a white background?

#129eb9 on white scores 3.17:1, which only clears AA for large text — 18.66px bold or 24px regular and up. Darken it to #0F8298 to reach 4.5:1, or #0B5E6F for 7:1.

What is the complementary color of #129eb9?

#B92D12 sits directly opposite on the wheel. Softer options are the split-complements #B9124A and #B98012, which give the same contrast with far less vibration.

What colors go well with #129eb9?

For interface work: #F4F9FA as the surface, #C0E5ED for borders, #4B8E9B for secondary text, #BD0E1D as an accent and #0B6374 for hover and pressed states. For a palette, the analogous pair #12B980 and #124AB9 stays calm, while #B92D12 is the loudest partner.

What is #129eb9 in CMYK for printing?

cmyk(90%, 15%, 0%, 28%). 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 #129eb9 warm or cool?

Cool — it scores 92 on a scale where 0 is the warmest orange and 100 the coolest azure. Nudged warmer it becomes #12B997; nudged cooler, #107EBB.

Which Tailwind color is closest to #129eb9?

The cyan family — its 500 step is #06b6d4, ΔE2000 7.1 away. That is a visible difference, so define #129eb9 as a custom token rather than reaching for the built-in.

How do I use #129eb9 in Tailwind CSS?

Inline it as an arbitrary value with bg-[#129eb9] or text-[#129eb9], 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 #129eb9 with 50% opacity?

rgba(18, 158, 185, 0.5), or #129eb980 in eight-digit hex. Over white that composites to #89CFDC; over black, #094F5D.

Is #129eb9 a web-safe color?

No. The nearest web-safe colour is #0099CC, ΔE2000 7.7 away. The palette only matters for legacy displays and some email clients now.

What does the color #129eb9 mean?

As a cyan, it reads clean, technical, fresh. Cyan reads as water, air and infrastructure: cool, hygienic, engineered. At this chroma the effect is amplified — it will dominate whatever sits beside it.

What gradient works with #129eb9?

The safest is same-hue elevation: linear-gradient(135deg, #1FC9E9, #129eb9 45%, #0B6374). For more colour, a short hue run to #0F1C9D keeps it rich without turning muddy.

Work with #129eb9 in the Color Lab

Every tool opens with this colour already loaded.

Every value on this page is computed from #129eb9 at request time — conversions, contrast ratios and ΔE distances are calculated, never looked up.