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cyan · cool

#18b3af

a dark, electric cyan · cool · closest name: Light Sea Green

Token name suggestion: Slate Teal

RGB
24, 179, 175
HSL
179°, 76%, 40%
CMYK
87, 0, 2, 30
Luminance
0.3553

#18b3af is a dark electric cyan, 179° on the wheel and 87/100 on the cool side. Put black text on it (8.11:1). As text it scores 2.59:1 on white — use #11827F instead. Nearest name is Light Sea Green, nearest Tailwind family is teal.

hsl(179 76% 40%)rgb(24 179 175)Base step 700AAA inkCool

At a glance

Every number on this page in one read: what #18b3af is made of, how bright it looks, and which way it leans.

Hex
#18b3af
Hue
179°
cyan
Saturation
76%
electric
Lightness
40%
dark
Brightness
70%
HSV value
Perceived
59%
weighted brightness
Luminance
0.3553
WCAG relative
Temperature
Cool
87/100 cool
Color family
Cyan
Tone
Electric
Best ink
Black
8.11:1
Closest name
Light Sea Green
ΔE2000 1.5
Chroma
38.1
LCH, 0–130ish
OKLCH L
0.695
perceptual lightness
Tailwind
teal
500 · ΔE 5.1
Web-safe
#00CC99
nearest of 216
Where it sits
Hue179° of 360°
Saturation76%
Lightness40%
Saturation × lightness field

Left edge is grey, right edge is full chroma; top is white, bottom is black. The dot is #18b3af.

Temperature
Warm ← → Cool87% 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
Red1%
Green91%
Blue9%

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

Every format

HEX#18b3af
HEX (8-digit)#18b3afff
RGBrgb(24, 179, 175)
RGBArgba(24, 179, 175, 1)
HSLhsl(179, 76%, 40%)
HSV / HSBhsv(178, 87%, 70%)
HWBhwb(179 9% 30%)
CMYKcmyk(87%, 0%, 2%, 30%)
LABlab(66.2 -37.1 -8.6)
LCHlch(66.2 38.1 193.0)
OKLCHoklch(0.695 0.116 191.9)
XYZ (D65)xyz(24.23, 35.53, 46.13)
Decimal1618863
Display P3color(display-p3 0.094 0.702 0.686)
Web-safe#00CC99

Copy-ready code

every platformclick to select
/* CSS */
color: #18b3af;
background-color: #18b3af;
/* CSS custom property */
--brand: #18b3af;
/* Tailwind (arbitrary) */
class="text-[#18b3af] bg-[#18b3af]"
/* SCSS */
$brand: #18b3af;
/* SwiftUI */
Color(red: 0.094, green: 0.702, blue: 0.686)
/* UIKit */
UIColor(red: 0.094, green: 0.702, blue: 0.686, alpha: 1)
/* Android XML */
<color name="brand">#18B3AF</color>
/* Android Compose */
Color(0xFF18B3AF)
/* Flutter */
Color(0xFF18B3AF)
/* Python / OpenCV (BGR) */
(175, 179, 24)
/* Python / PIL (RGB) */
(24, 179, 175)
/* Java AWT */
new Color(24, 179, 175)
/* .NET */
Color.FromArgb(255, 24, 179, 175)
/* OpenGL / Unity (0–1) */
(0.0941f, 0.7020f, 0.6863f, 1f)
/* LaTeX */
\definecolor{brand}{RGB}{24,179,175}
modern cssclick to select
/* mix without leaving CSS */
background: color-mix(in oklab, #18b3af 85%, white);
border-color: color-mix(in oklab, #18b3af 40%, transparent);
/* theme-aware in one line */
color: light-dark(#0F706E, #D3EEED);
/* relative colour syntax */
--hover: hsl(from #18b3af 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: #F3FCFC;
  --brand-100: #E7F9F8;
  --brand-200: #C8F4F3;
  --brand-300: #9CF2F0;
  --brand-400: #6BEBE8;
  --brand-500: #39E5E0;
  --brand-600: #1DD8D3;
  --brand-700: #18b3af;
  --brand-800: #13908D;
  --brand-900: #126866;
  --brand-950: #0B4140;
  --brand: #18b3af;
  --brand-ink: #000000;
  --brand-surface: #F4FAFA;
  --brand-border: #C0EDEC;
  --brand-hover: #149490;
  --brand-pressed: #107472;
}
@media (prefers-color-scheme: dark) {
  :root {
    --brand-surface: #142424;
    --brand-ink: #D3EEED;
  }
}
tailwind.config.jsclick to select
theme: {
  extend: {
    colors: {
      brand: {
        50: '#F3FCFC',
        100: '#E7F9F8',
        200: '#C8F4F3',
        300: '#9CF2F0',
        400: '#6BEBE8',
        500: '#39E5E0',
        600: '#1DD8D3',
        700: '#18b3af',
        800: '#13908D',
        900: '#126866',
        950: '#0B4140',
        DEFAULT: '#18b3af',
      },
    },
  },
}
scss mapclick to select
$brand: (
  '50': #F3FCFC,
  '100': #E7F9F8,
  '200': #C8F4F3,
  '300': #9CF2F0,
  '400': #6BEBE8,
  '500': #39E5E0,
  '600': #1DD8D3,
  '700': #18b3af,
  '800': #13908D,
  '900': #126866,
  '950': #0B4140,
);
$brand-base: #18b3af;
$brand-ink: #000000;

@function brand($step) { @return map-get($brand, $step); }
w3c design tokens (json)click to select
{
  "color": {
    "brand": {
      "50": { "$value": "#F3FCFC", "$type": "color" },
      "100": { "$value": "#E7F9F8", "$type": "color" },
      "200": { "$value": "#C8F4F3", "$type": "color" },
      "300": { "$value": "#9CF2F0", "$type": "color" },
      "400": { "$value": "#6BEBE8", "$type": "color" },
      "500": { "$value": "#39E5E0", "$type": "color" },
      "600": { "$value": "#1DD8D3", "$type": "color" },
      "700": { "$value": "#18b3af", "$type": "color" },
      "800": { "$value": "#13908D", "$type": "color" },
      "900": { "$value": "#126866", "$type": "color" },
      "950": { "$value": "#0B4140", "$type": "color" }
    },
    "brandInk": { "$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 #18b3af · 8.11:1
Use #000000AAA at every size.
Aa
12px
Aa
16px
Aa
24px
Aa
White text · 2.59:1
AA fail · AA large fail · AAA fail
Aa
Black text · 8.11:1 · recommended
AA pass · AA large pass · AAA pass
Reading the other direction: #18b3af as text scores 2.59:1 on white and 8.11:1 on black.
Best tinted ink on it, if plain black or white feels flat: #0F706E at 2.27:1.

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
#11827F · 4.64:1
AA on white−11% L
#11827F
The quick fox
#0D6260 · 7.16:1
AAA on white−18% L
#0D6260
The quick fox
#18b3af · 8.11:1
AA on blackalready passes
#18b3af
The quick fox
#18b3af · 8.11:1
AAA on blackalready passes
#18b3af

Large text — 24px regular or 18.66px bold and above — only needs 3:1, so #16A6A2 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
#18b3af on white: 2.59:1
AA ✗ fail · AA-large · AAA
Aa
#18b3af on black: 8.11:1
AA ✓ pass · AA-large · AAA
Against the neutral ladder

Contrast is symmetric, so each row covers both directions: #18b3af as text on that neutral, and that neutral as text on #18b3af.

NeutralRatioBoth directions
White2.59:1AaAa
Slate 502.48:1AaAa
Slate 1002.36:1AaAa
Slate 2002.10:1AaAa
Slate 3001.74:1AaAa
Slate 4001.01:1AaAa
Slate 5001.84:1AaAa
Slate 6002.92:1AaAa
Slate 7004.00:1AaAa
Slate 8005.65:1AaAa
Slate 9006.89:1AaAa
Black8.11:1AaAa
Colour vision deficiency
true color
protanopia · #A7A9AF
deuteranopia · #939BB0
tritanopia · #00B8B1

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. #18b3af 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.

#F3FCFC
#E7F9F8
#C8F4F3
#9CF2F0
#6BEBE8
#39E5E0
#1DD8D3
#18b3af
#13908D
#126866
#0B4140
Base = 700Lightest = 50 · #F3FCFCDarkest = 950 · #0B4140Text step on white = 900
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 0.029 191.9);
  --brand-100: oklch(0.94 0.046 191.9);
  --brand-200: oklch(0.88 0.069 191.9);
  --brand-300: oklch(0.80 0.090 191.9);
  --brand-400: oklch(0.72 0.107 191.9);
  --brand-500: oklch(0.64 0.116 191.9);
  --brand-600: oklch(0.56 0.116 191.9);
  --brand-700: oklch(0.48 0.109 191.9);
  --brand-800: oklch(0.40 0.097 191.9);
  --brand-900: oklch(0.32 0.081 191.9);
  --brand-950: oklch(0.24 0.064 191.9);
}

Colors that work with #18b3af

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#F4FAFA
Tinted page background
Border#C0EDEC
Hairlines and dividers
Muted text#4B9B99
Captions on the surface
Accent#B71441
Second voice, not a rival
Dark variant#0F706E
Hover, pressed, headers
Light variant#E9FCFC
Selected rows, tints
Dark surface#142424
Dark-mode background
Hover#149490
One step down in lightness
Pressed#107472
Two steps down
Disabled#88B3B2
Chroma pulled out
Focus ring#0FD0CB
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 #18b3af

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
  • Headers, footers and dark-mode surfaces
  • 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
  • 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
Not as text
Safe as a fill behind white type
No — use #0F706E
Safe as a 1px border on white
No — use #16A6A2

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#B3181C
Analogous left#18B362
Analogous right#1869B3
Split-complement 1#B31869
Split-complement 2#B36218
Triadic 1#AF18B3
Triadic 2#B3AF18
Tetradic#6218B3
On the wheel
Base+30°−30°+120°+240°+180°179°

#18b3af sits at 179°. Every dot is a harmony position and links to its own page in the table alongside.

RGB percentages

Red9.4%
Green70.2%
Blue68.6%
R · 0–255
24
0x18
G · 0–255
179
0xb3
B · 0–255
175
0xaf

CMYK percentages

Cyan86.6%
Magenta0.0%
Yellow2.2%
Key (black)29.8%

Total ink coverage is 119%. Most commercial presses cap around 300% — above that, sheets stop drying properly.

Color previews

#18b3af text on a black background

contrast 8.11:1

Card sample

#18b3af text on a white background

contrast 2.59:1

Card sample

#18b3af on grey

2.36:1

#18b3af on its own surface

2.46:1

#18b3af on its dark surface

6.20:1

CSS3 live lab

Text font color

The quick brown fox

color: #18b3af;
Background color
Panel with #18b3af background
background-color: #18b3af;
Text shadow — hex

Glowing headline

text-shadow: 2px 2px 8px #18b3af;
Text shadow — RGB

Soft neon halo

text-shadow: 0 0 14px rgba(24, 179, 175, 0.45);
Div box shadow
Elevated card
box-shadow: 0 12px 32px -8px rgba(24, 179, 175, 0.45);
Border & gradient
Gradient panel
border: 3px solid #18b3af;
background: linear-gradient(135deg, #18b3af, #1850B3);
Gradient text

Gradient headline

background: linear-gradient(90deg, #18b3af, #1829B3);
-webkit-background-clip: text;
color: transparent;
Focus ring
Focused control
outline: 2px solid #18b3af;
outline-offset: 3px;
Underline & caret

Marked up text

text-decoration-color: #18b3af;
caret-color: #18b3af;
Left rule
Pull quote or callout
border-left: 4px solid #18b3af;
Ring + tint
Selected chip
background: #E9FCFC;
box-shadow: inset 0 0 0 2px #18b3af;
Conic badge
68%
background: conic-gradient(#18b3af 68%, #e2e8f0 0);

Transparency

What each alpha value actually composites to. The top row is #18b3af 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(24, 179, 175, 0.5)
rgb(24 179 175 / 50%)
#18b3af80
hsl(179 76% 40% / 50%)
color-mix(in srgb, #18b3af 50%, transparent)
Alpha8-digit hexFlat on white
10%#18b3af1a#E8F7F7
20%#18b3af33#D1F0EF
40%#18b3af66#A3E1DF
60%#18b3af99#74D1CF
80%#18b3afcc#46C2BF

Gradients from #18b3af

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, #26E2DD, #18b3af 45%, #0F706E);
Duotone
A short hue run reads richer than a flat fill
background: linear-gradient(120deg, #18b3af, #143998);
Complement sweep
Loud — keep it behind large type only
background: linear-gradient(90deg, #18b3af, #B3181C);
Spotlight
Hero panels and app headers
background: radial-gradient(120% 120% at 20% 0%, #41E6E1 0%, #18b3af 45%, #0F706E 100%);
Soft wash
Section backgrounds that stay readable
background: linear-gradient(180deg, #F4FAFA, #ffffff);
Mesh
Ambient background, no image weight
background: radial-gradient(60% 60% at 15% 20%, #1EE06A 0%, transparent 60%), radial-gradient(55% 55% at 85% 15%, #1C6ACE 0%, transparent 60%), radial-gradient(70% 70% at 50% 95%, #0F706E 0%, transparent 65%), #18b3af;

Monochromatic scale

Palettes built from #18b3af

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.

#18b3af 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 8.11:1.

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.

#18b3af, answered

What color is #18b3af?

#18b3af is a dark electric cyan, closest to Light Sea Green (ΔE2000 1.5). It sits at 179° on the hue wheel with 76% saturation and 40% lightness, which reads as cool.

What is the RGB value of #18b3af?

rgb(24, 179, 175) — 24 red, 179 green and 175 blue out of 255, or 9.4% / 70.2% / 68.6% by channel.

What is #18b3af in HSL and HSV?

hsl(179, 76%, 40%) and hsv(178, 87%, 70%). HSL is what CSS takes; HSV is what your design tool's picker shows, which is why the saturation numbers rarely match.

Is #18b3af a light or a dark color?

It is a mid-tone. Relative luminance is 0.3553 and perceived brightness is 59%, so black text on it reaches 8.11:1.

Should I use black or white text on #18b3af?

Black. It scores 8.11:1 against #18b3af, versus 2.59:1 for white — AAA at any size.

Is #18b3af accessible on a white background?

#18b3af on white scores 2.59:1, which fails WCAG AA at every size. Darken it to #11827F to reach 4.5:1, or #0D6260 for 7:1.

What is the complementary color of #18b3af?

#B3181C sits directly opposite on the wheel. Softer options are the split-complements #B31869 and #B36218, which give the same contrast with far less vibration.

What colors go well with #18b3af?

For interface work: #F4FAFA as the surface, #C0EDEC for borders, #4B9B99 for secondary text, #B71441 as an accent and #0F706E for hover and pressed states. For a palette, the analogous pair #18B362 and #1869B3 stays calm, while #B3181C is the loudest partner.

What is #18b3af in CMYK for printing?

cmyk(87%, 0%, 2%, 30%). 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 #18b3af warm or cool?

Cool — it scores 87 on a scale where 0 is the warmest orange and 100 the coolest azure. Nudged warmer it becomes #18B376; nudged cooler, #1688B5.

Which Tailwind color is closest to #18b3af?

The teal family — its 500 step is #14b8a6, ΔE2000 5.1 away. That is a visible difference, so define #18b3af as a custom token rather than reaching for the built-in.

How do I use #18b3af in Tailwind CSS?

Inline it as an arbitrary value with bg-[#18b3af] or text-[#18b3af], 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 #18b3af with 50% opacity?

rgba(24, 179, 175, 0.5), or #18b3af80 in eight-digit hex. Over white that composites to #8CD9D7; over black, #0C5A58.

Is #18b3af a web-safe color?

No. The nearest web-safe colour is #00CC99, ΔE2000 15 away. The palette only matters for legacy displays and some email clients now.

What does the color #18b3af 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 #18b3af?

The safest is same-hue elevation: linear-gradient(135deg, #26E2DD, #18b3af 45%, #0F706E). For more colour, a short hue run to #143998 keeps it rich without turning muddy.

Work with #18b3af in the Color Lab

Every tool opens with this colour already loaded.

Every value on this page is computed from #18b3af at request time — conversions, contrast ratios and ΔE distances are calculated, never looked up.