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cyan · cool

#218abc

a dark, vivid cyan · cool · closest name: Steel Blue

Token name suggestion: Dusk Reef

RGB
33, 138, 188
HSL
199°, 70%, 43%
CMYK
82, 27, 0, 26
Luminance
0.2213

#218abc is a dark vivid cyan, 199° on the wheel and 96/100 on the cool side. Put black text on it (5.43:1). As text it scores 3.87:1 on white — large text only. Nearest name is Steel Blue, nearest Tailwind family is sky.

hsl(199 70% 43%)rgb(33 138 188)Base step 700AA inkCool

At a glance

Every number on this page in one read: what #218abc is made of, how bright it looks, and which way it leans.

Hex
#218abc
Hue
199°
cyan
Saturation
70%
vivid
Lightness
43%
dark
Brightness
74%
HSV value
Perceived
49%
weighted brightness
Luminance
0.2213
WCAG relative
Temperature
Cool
96/100 cool
Color family
Cyan
Tone
Vivid
Best ink
Black
5.43:1
Closest name
Steel Blue
ΔE2000 5.3
Chroma
36.0
LCH, 0–130ish
OKLCH L
0.600
perceptual lightness
Tailwind
sky
500 · ΔE 9.3
Web-safe
#3399CC
nearest of 216
Where it sits
Hue199° of 360°
Saturation70%
Lightness43%
Saturation × lightness field

Left edge is grey, right edge is full chroma; top is white, bottom is black. The dot is #218abc.

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
Red1%
Green82%
Blue16%

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

Every format

HEX#218abc
HEX (8-digit)#218abcff
RGBrgb(33, 138, 188)
RGBArgba(33, 138, 188, 1)
HSLhsl(199, 70%, 43%)
HSV / HSBhsv(199, 82%, 74%)
HWBhwb(199 13% 26%)
CMYKcmyk(82%, 27%, 0%, 26%)
LABlab(54.2 -11.2 -34.2)
LCHlch(54.2 36.0 251.9)
OKLCHoklch(0.600 0.118 235.3)
XYZ (D65)xyz(18.79, 22.13, 50.85)
Decimal2198204
Display P3color(display-p3 0.129 0.541 0.737)
Web-safe#3399CC

Copy-ready code

every platformclick to select
/* CSS */
color: #218abc;
background-color: #218abc;
/* CSS custom property */
--brand: #218abc;
/* Tailwind (arbitrary) */
class="text-[#218abc] bg-[#218abc]"
/* SCSS */
$brand: #218abc;
/* SwiftUI */
Color(red: 0.129, green: 0.541, blue: 0.737)
/* UIKit */
UIColor(red: 0.129, green: 0.541, blue: 0.737, alpha: 1)
/* Android XML */
<color name="brand">#218ABC</color>
/* Android Compose */
Color(0xFF218ABC)
/* Flutter */
Color(0xFF218ABC)
/* Python / OpenCV (BGR) */
(188, 138, 33)
/* Python / PIL (RGB) */
(33, 138, 188)
/* Java AWT */
new Color(33, 138, 188)
/* .NET */
Color.FromArgb(255, 33, 138, 188)
/* OpenGL / Unity (0–1) */
(0.1294f, 0.5412f, 0.7373f, 1f)
/* LaTeX */
\definecolor{brand}{RGB}{33,138,188}
modern cssclick to select
/* mix without leaving CSS */
background: color-mix(in oklab, #218abc 85%, white);
border-color: color-mix(in oklab, #218abc 40%, transparent);
/* theme-aware in one line */
color: light-dark(#13506C, #D3E5EE);
/* relative colour syntax */
--hover: hsl(from #218abc 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: #F3F9FC;
  --brand-100: #E7F3F8;
  --brand-200: #C9E5F2;
  --brand-300: #A0D5EE;
  --brand-400: #70C0E6;
  --brand-500: #40ABDD;
  --brand-600: #2599D0;
  --brand-700: #218abc;
  --brand-800: #18668B;
  --brand-900: #164B65;
  --brand-950: #0E2F3F;
  --brand: #218abc;
  --brand-ink: #000000;
  --brand-surface: #F4F8FA;
  --brand-border: #C0DEED;
  --brand-hover: #1C739D;
  --brand-pressed: #165D7F;
}
@media (prefers-color-scheme: dark) {
  :root {
    --brand-surface: #141F24;
    --brand-ink: #D3E5EE;
  }
}
tailwind.config.jsclick to select
theme: {
  extend: {
    colors: {
      brand: {
        50: '#F3F9FC',
        100: '#E7F3F8',
        200: '#C9E5F2',
        300: '#A0D5EE',
        400: '#70C0E6',
        500: '#40ABDD',
        600: '#2599D0',
        700: '#218abc',
        800: '#18668B',
        900: '#164B65',
        950: '#0E2F3F',
        DEFAULT: '#218abc',
      },
    },
  },
}
scss mapclick to select
$brand: (
  '50': #F3F9FC,
  '100': #E7F3F8,
  '200': #C9E5F2,
  '300': #A0D5EE,
  '400': #70C0E6,
  '500': #40ABDD,
  '600': #2599D0,
  '700': #218abc,
  '800': #18668B,
  '900': #164B65,
  '950': #0E2F3F,
);
$brand-base: #218abc;
$brand-ink: #000000;

@function brand($step) { @return map-get($brand, $step); }
w3c design tokens (json)click to select
{
  "color": {
    "brand": {
      "50": { "$value": "#F3F9FC", "$type": "color" },
      "100": { "$value": "#E7F3F8", "$type": "color" },
      "200": { "$value": "#C9E5F2", "$type": "color" },
      "300": { "$value": "#A0D5EE", "$type": "color" },
      "400": { "$value": "#70C0E6", "$type": "color" },
      "500": { "$value": "#40ABDD", "$type": "color" },
      "600": { "$value": "#2599D0", "$type": "color" },
      "700": { "$value": "#218abc", "$type": "color" },
      "800": { "$value": "#18668B", "$type": "color" },
      "900": { "$value": "#164B65", "$type": "color" },
      "950": { "$value": "#0E2F3F", "$type": "color" }
    },
    "brandInk": { "$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 #218abc · 5.43:1
Use #000000AA at every size, AAA for large text only.
Aa
12px
Aa
16px
Aa
24px
Aa
White text · 3.87:1
AA fail · AA large pass · AAA fail
Aa
Black text · 5.43:1 · recommended
AA pass · AA large pass · AAA fail
Reading the other direction: #218abc as text scores 3.87:1 on white and 5.43:1 on black.
Best tinted ink on it, if plain black or white feels flat: #13506C 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
#1E7DAA · 4.60:1
AA on white−4% L
#1E7DAA
The quick fox
#165D7F · 7.23:1
AAA on white−14% L
#165D7F
The quick fox
#218abc · 5.43:1
AA on blackalready passes
#218abc
The quick fox
#27A0D9 · 7.12:1
AAA on black+7% L
#27A0D9

Large text — 24px regular or 18.66px bold and above — only needs 3:1, so #218ABC 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
#218abc on white: 3.87:1
AA ✗ fail · AA-large · AAA
Aa
#218abc on black: 5.43:1
AA ✓ pass · AA-large · AAA
Against the neutral ladder

Contrast is symmetric, so each row covers both directions: #218abc as text on that neutral, and that neutral as text on #218abc.

NeutralRatioBoth directions
White3.87:1AaAa
Slate 503.70:1AaAa
Slate 1003.53:1AaAa
Slate 2003.14:1AaAa
Slate 3002.61:1AaAa
Slate 4001.51:1AaAa
Slate 5001.23:1AaAa
Slate 6001.96:1AaAa
Slate 7002.68:1AaAa
Slate 8003.78:1AaAa
Slate 9004.61:1AaAa
Black5.43:1AaAa
Colour vision deficiency
true color
protanopia · #7289BE
deuteranopia · #5D7BBB
tritanopia · #00979B

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. #218abc 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.

#F3F9FC
#E7F3F8
#C9E5F2
#A0D5EE
#70C0E6
#40ABDD
#2599D0
#218abc
#18668B
#164B65
#0E2F3F
Base = 700Lightest = 50 · #F3F9FCDarkest = 950 · #0E2F3FText 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 0.029 235.3);
  --brand-100: oklch(0.94 0.047 235.3);
  --brand-200: oklch(0.88 0.071 235.3);
  --brand-300: oklch(0.80 0.092 235.3);
  --brand-400: oklch(0.72 0.108 235.3);
  --brand-500: oklch(0.64 0.118 235.3);
  --brand-600: oklch(0.56 0.118 235.3);
  --brand-700: oklch(0.48 0.111 235.3);
  --brand-800: oklch(0.40 0.099 235.3);
  --brand-900: oklch(0.32 0.082 235.3);
  --brand-950: oklch(0.24 0.065 235.3);
}

Colors that work with #218abc

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#F4F8FA
Tinted page background
Border#C0DEED
Hairlines and dividers
Muted text#4B819B
Captions on the surface
Accent#C0291D
Second voice, not a rival
Dark variant#13506C
Hover, pressed, headers
Light variant#E9F5FB
Selected rows, tints
Dark surface#141F24
Dark-mode background
Hover#1C739D
One step down in lightness
Pressed#165D7F
Two steps down
Disabled#93ADBA
Chroma pulled out
Focus ring#189BD9
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 #218abc

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 #13506C
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.

This is a confident chroma: strong enough to lead a brand, restrained enough to live in an interface all day. 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
  • EnergyMedium-high
  • Weight57/100
  • 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#BC5321
Analogous left#21BCA0
Analogous right#213CBC
Split-complement 1#BC213C
Split-complement 2#BCA021
Triadic 1#BC218A
Triadic 2#8ABC21
Tetradic#A021BC
On the wheel
Base+30°−30°+120°+240°+180°199°

#218abc sits at 199°. Every dot is a harmony position and links to its own page in the table alongside.

RGB percentages

Red12.9%
Green54.1%
Blue73.7%
R · 0–255
33
0x21
G · 0–255
138
0x8a
B · 0–255
188
0xbc

CMYK percentages

Cyan82.4%
Magenta26.6%
Yellow0.0%
Key (black)26.3%

Total ink coverage is 135%. Most commercial presses cap around 300% — above that, sheets stop drying properly.

Color previews

#218abc text on a black background

contrast 5.43:1

Card sample

#218abc text on a white background

contrast 3.87:1

Card sample

#218abc on grey

3.53:1

#218abc on its own surface

3.62:1

#218abc on its dark surface

4.34:1

CSS3 live lab

Text font color

The quick brown fox

color: #218abc;
Background color
Panel with #218abc background
background-color: #218abc;
Text shadow — hex

Glowing headline

text-shadow: 2px 2px 8px #218abc;
Text shadow — RGB

Soft neon halo

text-shadow: 0 0 14px rgba(33, 138, 188, 0.45);
Div box shadow
Elevated card
box-shadow: 0 12px 32px -8px rgba(33, 138, 188, 0.45);
Border & gradient
Gradient panel
border: 3px solid #218abc;
background: linear-gradient(135deg, #218abc, #2123BC);
Gradient text

Gradient headline

background: linear-gradient(90deg, #218abc, #4621BC);
-webkit-background-clip: text;
color: transparent;
Focus ring
Focused control
outline: 2px solid #218abc;
outline-offset: 3px;
Underline & caret

Marked up text

text-decoration-color: #218abc;
caret-color: #218abc;
Left rule
Pull quote or callout
border-left: 4px solid #218abc;
Ring + tint
Selected chip
background: #E9F5FB;
box-shadow: inset 0 0 0 2px #218abc;
Conic badge
68%
background: conic-gradient(#218abc 68%, #e2e8f0 0);

Transparency

What each alpha value actually composites to. The top row is #218abc 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(33, 138, 188, 0.5)
rgb(33 138 188 / 50%)
#218abc80
hsl(199 70% 43% / 50%)
color-mix(in srgb, #218abc 50%, transparent)
Alpha8-digit hexFlat on white
10%#218abc1a#E9F3F8
20%#218abc33#D3E8F2
40%#218abc66#A6D0E4
60%#218abc99#7AB9D7
80%#218abccc#4DA1C9

Gradients from #218abc

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, #3DA9DD, #218abc 45%, #13506C);
Duotone
A short hue run reads richer than a flat fill
background: linear-gradient(120deg, #218abc, #261CA2);
Complement sweep
Loud — keep it behind large type only
background: linear-gradient(90deg, #218abc, #BC5321);
Spotlight
Hero panels and app headers
background: radial-gradient(120% 120% at 20% 0%, #57B5E1 0%, #218abc 45%, #13506C 100%);
Soft wash
Section backgrounds that stay readable
background: linear-gradient(180deg, #F4F8FA, #ffffff);
Mesh
Ambient background, no image weight
background: radial-gradient(60% 60% at 15% 20%, #34DBB0 0%, transparent 60%), radial-gradient(55% 55% at 85% 15%, #2636D6 0%, transparent 60%), radial-gradient(70% 70% at 50% 95%, #13506C 0%, transparent 65%), #218abc;

Monochromatic scale

Palettes built from #218abc

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.

#218abc 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

Converts to four-color process without much drama. Proof it anyway.

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 5.43:1.

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.

#218abc, answered

What color is #218abc?

#218abc is a dark vivid cyan, closest to Steel Blue (ΔE2000 5.3). It sits at 199° on the hue wheel with 70% saturation and 43% lightness, which reads as cool.

What is the RGB value of #218abc?

rgb(33, 138, 188) — 33 red, 138 green and 188 blue out of 255, or 12.9% / 54.1% / 73.7% by channel.

What is #218abc in HSL and HSV?

hsl(199, 70%, 43%) and hsv(199, 82%, 74%). HSL is what CSS takes; HSV is what your design tool's picker shows, which is why the saturation numbers rarely match.

Is #218abc a light or a dark color?

It is a mid-tone. Relative luminance is 0.2213 and perceived brightness is 49%, so black text on it reaches 5.43:1.

Should I use black or white text on #218abc?

Black. It scores 5.43:1 against #218abc, versus 3.87:1 for white — AA at any size.

Is #218abc accessible on a white background?

#218abc on white scores 3.87:1, which only clears AA for large text — 18.66px bold or 24px regular and up. Darken it to #1E7DAA to reach 4.5:1, or #165D7F for 7:1.

What is the complementary color of #218abc?

#BC5321 sits directly opposite on the wheel. Softer options are the split-complements #BC213C and #BCA021, which give the same contrast with far less vibration.

What colors go well with #218abc?

For interface work: #F4F8FA as the surface, #C0DEED for borders, #4B819B for secondary text, #C0291D as an accent and #13506C for hover and pressed states. For a palette, the analogous pair #21BCA0 and #213CBC stays calm, while #BC5321 is the loudest partner.

What is #218abc in CMYK for printing?

cmyk(82%, 27%, 0%, 26%). This is a screen-to-ink approximation — ask your printer for a proof before committing to a run.

Is #218abc 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 #21BCB5; nudged cooler, #1F78BE.

Which Tailwind color is closest to #218abc?

The sky family — its 500 step is #0ea5e9, ΔE2000 9.3 away. That is a visible difference, so define #218abc as a custom token rather than reaching for the built-in.

How do I use #218abc in Tailwind CSS?

Inline it as an arbitrary value with bg-[#218abc] or text-[#218abc], 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 #218abc with 50% opacity?

rgba(33, 138, 188, 0.5), or #218abc80 in eight-digit hex. Over white that composites to #90C5DE; over black, #11455E.

Is #218abc a web-safe color?

No. The nearest web-safe colour is #3399CC, ΔE2000 5.2 away. The palette only matters for legacy displays and some email clients now.

What does the color #218abc 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 #218abc?

The safest is same-hue elevation: linear-gradient(135deg, #3DA9DD, #218abc 45%, #13506C). For more colour, a short hue run to #261CA2 keeps it rich without turning muddy.

Work with #218abc in the Color Lab

Every tool opens with this colour already loaded.

Every value on this page is computed from #218abc at request time — conversions, contrast ratios and ΔE distances are calculated, never looked up.