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cyan · cool

#51a2ab

a balanced, soft cyan · cool · closest name: Cadet Blue

Token name suggestion: Atlas Reef

RGB
81, 162, 171
HSL
186°, 36%, 49%
CMYK
53, 5, 0, 33
Luminance
0.3053

#51a2ab is a balanced soft cyan, 186° on the wheel and 90/100 on the cool side. Put black text on it (7.11:1). As text it scores 2.96:1 on white — use #3F7E85 instead. Nearest name is Cadet Blue, nearest Tailwind family is cyan.

hsl(186 36% 49%)rgb(81 162 171)Base step 600AAA inkCool

At a glance

Every number on this page in one read: what #51a2ab is made of, how bright it looks, and which way it leans.

Hex
#51a2ab
Hue
186°
cyan
Saturation
36%
soft
Lightness
49%
balanced
Brightness
67%
HSV value
Perceived
56%
weighted brightness
Luminance
0.3053
WCAG relative
Temperature
Cool
90/100 cool
Color family
Cyan
Tone
Soft
Best ink
Black
7.11:1
Closest name
Cadet Blue
ΔE2000 3.3
Chroma
25.3
LCH, 0–130ish
OKLCH L
0.665
perceptual lightness
Tailwind
cyan
500 · ΔE 8.6
Web-safe
#669999
nearest of 216
Where it sits
Hue186° of 360°
Saturation36%
Lightness49%
Saturation × lightness field

Left edge is grey, right edge is full chroma; top is white, bottom is black. The dot is #51a2ab.

Temperature
Warm ← → Cool90% 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
Red6%
Green85%
Blue10%

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

Every format

HEX#51a2ab
HEX (8-digit)#51a2abff
RGBrgb(81, 162, 171)
RGBArgba(81, 162, 171, 1)
HSLhsl(186, 36%, 49%)
HSV / HSBhsv(186, 53%, 67%)
HWBhwb(186 32% 33%)
CMYKcmyk(53%, 5%, 0%, 33%)
LABlab(62.1 -22.1 -12.3)
LCHlch(62.1 25.3 209.0)
OKLCHoklch(0.665 0.080 205.0)
XYZ (D65)xyz(23.66, 30.53, 43.17)
Decimal5350059
Display P3color(display-p3 0.318 0.635 0.671)
Web-safe#669999

Copy-ready code

every platformclick to select
/* CSS */
color: #51a2ab;
background-color: #51a2ab;
/* CSS custom property */
--brand: #51a2ab;
/* Tailwind (arbitrary) */
class="text-[#51a2ab] bg-[#51a2ab]"
/* SCSS */
$brand: #51a2ab;
/* SwiftUI */
Color(red: 0.318, green: 0.635, blue: 0.671)
/* UIKit */
UIColor(red: 0.318, green: 0.635, blue: 0.671, alpha: 1)
/* Android XML */
<color name="brand">#51A2AB</color>
/* Android Compose */
Color(0xFF51A2AB)
/* Flutter */
Color(0xFF51A2AB)
/* Python / OpenCV (BGR) */
(171, 162, 81)
/* Python / PIL (RGB) */
(81, 162, 171)
/* Java AWT */
new Color(81, 162, 171)
/* .NET */
Color.FromArgb(255, 81, 162, 171)
/* OpenGL / Unity (0–1) */
(0.3176f, 0.6353f, 0.6706f, 1f)
/* LaTeX */
\definecolor{brand}{RGB}{81,162,171}
modern cssclick to select
/* mix without leaving CSS */
background: color-mix(in oklab, #51a2ab 85%, white);
border-color: color-mix(in oklab, #51a2ab 40%, transparent);
/* theme-aware in one line */
color: light-dark(#295257, #D5E9EB);
/* relative colour syntax */
--hover: hsl(from #51a2ab 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: #F5F9F9;
  --brand-100: #EBF3F4;
  --brand-200: #D3E6E8;
  --brand-300: #B3D7DB;
  --brand-400: #8DC3C9;
  --brand-500: #67AFB7;
  --brand-600: #51a2ab;
  --brand-700: #42838A;
  --brand-800: #34696F;
  --brand-900: #294D51;
  --brand-950: #1A3033;
  --brand: #51a2ab;
  --brand-ink: #000000;
  --brand-surface: #F5FAFA;
  --brand-border: #C8E2E5;
  --brand-hover: #468B93;
  --brand-pressed: #3A747A;
}
@media (prefers-color-scheme: dark) {
  :root {
    --brand-surface: #142324;
    --brand-ink: #D5E9EB;
  }
}
tailwind.config.jsclick to select
theme: {
  extend: {
    colors: {
      brand: {
        50: '#F5F9F9',
        100: '#EBF3F4',
        200: '#D3E6E8',
        300: '#B3D7DB',
        400: '#8DC3C9',
        500: '#67AFB7',
        600: '#51a2ab',
        700: '#42838A',
        800: '#34696F',
        900: '#294D51',
        950: '#1A3033',
        DEFAULT: '#51a2ab',
      },
    },
  },
}
scss mapclick to select
$brand: (
  '50': #F5F9F9,
  '100': #EBF3F4,
  '200': #D3E6E8,
  '300': #B3D7DB,
  '400': #8DC3C9,
  '500': #67AFB7,
  '600': #51a2ab,
  '700': #42838A,
  '800': #34696F,
  '900': #294D51,
  '950': #1A3033,
);
$brand-base: #51a2ab;
$brand-ink: #000000;

@function brand($step) { @return map-get($brand, $step); }
w3c design tokens (json)click to select
{
  "color": {
    "brand": {
      "50": { "$value": "#F5F9F9", "$type": "color" },
      "100": { "$value": "#EBF3F4", "$type": "color" },
      "200": { "$value": "#D3E6E8", "$type": "color" },
      "300": { "$value": "#B3D7DB", "$type": "color" },
      "400": { "$value": "#8DC3C9", "$type": "color" },
      "500": { "$value": "#67AFB7", "$type": "color" },
      "600": { "$value": "#51a2ab", "$type": "color" },
      "700": { "$value": "#42838A", "$type": "color" },
      "800": { "$value": "#34696F", "$type": "color" },
      "900": { "$value": "#294D51", "$type": "color" },
      "950": { "$value": "#1A3033", "$type": "color" }
    },
    "brandInk": { "$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 #51a2ab · 7.11:1
Use #000000AAA at every size.
Aa
12px
Aa
16px
Aa
24px
Aa
White text · 2.96:1
AA fail · AA large fail · AAA fail
Aa
Black text · 7.11:1 · recommended
AA pass · AA large pass · AAA pass
Reading the other direction: #51a2ab as text scores 2.96:1 on white and 7.11:1 on black.
Best tinted ink on it, if plain black or white feels flat: #295257 at 2.91:1.

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
#3F7E85 · 4.63:1
AA on white−11% L
#3F7E85
The quick fox
#306066 · 7.02:1
AAA on white−20% L
#306066
The quick fox
#51a2ab · 7.11:1
AA on blackalready passes
#51a2ab
The quick fox
#51a2ab · 7.11:1
AAA on blackalready passes
#51a2ab

Large text — 24px regular or 18.66px bold and above — only needs 3:1, so #4F9FA7 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
#51a2ab on white: 2.96:1
AA ✗ fail · AA-large · AAA
Aa
#51a2ab on black: 7.11:1
AA ✓ pass · AA-large · AAA
Against the neutral ladder

Contrast is symmetric, so each row covers both directions: #51a2ab as text on that neutral, and that neutral as text on #51a2ab.

NeutralRatioBoth directions
White2.96:1AaAa
Slate 502.82:1AaAa
Slate 1002.70:1AaAa
Slate 2002.40:1AaAa
Slate 3001.99:1AaAa
Slate 4001.15:1AaAa
Slate 5001.61:1AaAa
Slate 6002.56:1AaAa
Slate 7003.50:1AaAa
Slate 8004.95:1AaAa
Slate 9006.04:1AaAa
Black7.11:1AaAa
Colour vision deficiency
true color
protanopia · #979CAC
deuteranopia · #8992AB
tritanopia · #09A8A5

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. #51a2ab is pinned to step 600; the rest hold its hue and let saturation ease off at the extremes so the pale end never turns neon.

#F5F9F9
#EBF3F4
#D3E6E8
#B3D7DB
#8DC3C9
#67AFB7
#51a2ab
#42838A
#34696F
#294D51
#1A3033
Base = 600Lightest = 50 · #F5F9F9Darkest = 950 · #1A3033Text 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 0.020 205.0);
  --brand-100: oklch(0.94 0.032 205.0);
  --brand-200: oklch(0.88 0.048 205.0);
  --brand-300: oklch(0.80 0.062 205.0);
  --brand-400: oklch(0.72 0.074 205.0);
  --brand-500: oklch(0.64 0.080 205.0);
  --brand-600: oklch(0.56 0.080 205.0);
  --brand-700: oklch(0.48 0.075 205.0);
  --brand-800: oklch(0.40 0.067 205.0);
  --brand-900: oklch(0.32 0.056 205.0);
  --brand-950: oklch(0.24 0.044 205.0);
}

Colors that work with #51a2ab

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#F5FAFA
Tinted page background
Border#C8E2E5
Hairlines and dividers
Muted text#4B939B
Captions on the surface
Accent#B04C5B
Second voice, not a rival
Dark variant#295257
Hover, pressed, headers
Light variant#EEF6F7
Selected rows, tints
Dark surface#142324
Dark-mode background
Hover#468B93
One step down in lightness
Pressed#3A747A
Two steps down
Disabled#A6C3C6
Chroma pulled out
Focus ring#52B4BE
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 #51a2ab

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

Works well for
  • Text and icons on dark surfaces
  • Charts, tags and secondary surfaces
  • Brand accents, badges and data highlights
  • Chart series and data categories
Use with care
  • Text of any size on white — fails WCAG AA
  • 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 #295257
Safe as a 1px border on white
No — use #4F9FA7

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.

The muted chroma softens the association — it reads considered rather than loud, which suits long-form and data-heavy screens. The mid lightness keeps it versatile in both themes.

Worth knowing

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

Reads as
  • FormalityMedium
  • EnergyMedium
  • Weight51/100
  • 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#AB5A51
Analogous left#51AB87
Analogous right#5175AB
Split-complement 1#AB5175
Split-complement 2#AB8751
Triadic 1#AB51A2
Triadic 2#A2AB51
Tetradic#8751AB
On the wheel
Base+30°−30°+120°+240°+180°186°

#51a2ab sits at 186°. Every dot is a harmony position and links to its own page in the table alongside.

RGB percentages

Red31.8%
Green63.5%
Blue67.1%
R · 0–255
81
0x51
G · 0–255
162
0xa2
B · 0–255
171
0xab

CMYK percentages

Cyan52.6%
Magenta5.3%
Yellow0.0%
Key (black)32.9%

Total ink coverage is 91%. Most commercial presses cap around 300% — above that, sheets stop drying properly.

Color previews

#51a2ab text on a black background

contrast 7.11:1

Card sample

#51a2ab text on a white background

contrast 2.96:1

Card sample

#51a2ab on grey

2.70:1

#51a2ab on its own surface

2.81:1

#51a2ab on its dark surface

5.48:1

CSS3 live lab

Text font color

The quick brown fox

color: #51a2ab;
Background color
Panel with #51a2ab background
background-color: #51a2ab;
Text shadow — hex

Glowing headline

text-shadow: 2px 2px 8px #51a2ab;
Text shadow — RGB

Soft neon halo

text-shadow: 0 0 14px rgba(81, 162, 171, 0.45);
Div box shadow
Elevated card
box-shadow: 0 12px 32px -8px rgba(81, 162, 171, 0.45);
Border & gradient
Gradient panel
border: 3px solid #51a2ab;
background: linear-gradient(135deg, #51a2ab, #5166AB);
Gradient text

Gradient headline

background: linear-gradient(90deg, #51a2ab, #5251AB);
-webkit-background-clip: text;
color: transparent;
Focus ring
Focused control
outline: 2px solid #51a2ab;
outline-offset: 3px;
Underline & caret

Marked up text

text-decoration-color: #51a2ab;
caret-color: #51a2ab;
Left rule
Pull quote or callout
border-left: 4px solid #51a2ab;
Ring + tint
Selected chip
background: #EEF6F7;
box-shadow: inset 0 0 0 2px #51a2ab;
Conic badge
68%
background: conic-gradient(#51a2ab 68%, #e2e8f0 0);

Transparency

What each alpha value actually composites to. The top row is #51a2ab 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(81, 162, 171, 0.5)
rgb(81 162 171 / 50%)
#51a2ab80
hsl(186 36% 49% / 50%)
color-mix(in srgb, #51a2ab 50%, transparent)
Alpha8-digit hexFlat on white
10%#51a2ab1a#EEF6F7
20%#51a2ab33#DCECEE
40%#51a2ab66#B9DADD
60%#51a2ab99#97C7CD
80%#51a2abcc#74B5BC

Gradients from #51a2ab

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, #79B9C0, #51a2ab 45%, #295257);
Duotone
A short hue run reads richer than a flat fill
background: linear-gradient(120deg, #51a2ab, #475396);
Complement sweep
Loud — keep it behind large type only
background: linear-gradient(90deg, #51a2ab, #AB5A51);
Spotlight
Hero panels and app headers
background: radial-gradient(120% 120% at 20% 0%, #8EC4CA 0%, #51a2ab 45%, #295257 100%);
Soft wash
Section backgrounds that stay readable
background: linear-gradient(180deg, #F5FAFA, #ffffff);
Mesh
Ambient background, no image weight
background: radial-gradient(60% 60% at 15% 20%, #73BC99 0%, transparent 60%), radial-gradient(55% 55% at 85% 15%, #657EB6 0%, transparent 60%), radial-gradient(70% 70% at 50% 95%, #295257 0%, transparent 65%), #51a2ab;

Monochromatic scale

Palettes built from #51a2ab

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.

#51a2ab 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 7.11:1.

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.

#51a2ab, answered

What color is #51a2ab?

#51a2ab is a balanced soft cyan, closest to Cadet Blue (ΔE2000 3.3). It sits at 186° on the hue wheel with 36% saturation and 49% lightness, which reads as cool.

What is the RGB value of #51a2ab?

rgb(81, 162, 171) — 81 red, 162 green and 171 blue out of 255, or 31.8% / 63.5% / 67.1% by channel.

What is #51a2ab in HSL and HSV?

hsl(186, 36%, 49%) and hsv(186, 53%, 67%). HSL is what CSS takes; HSV is what your design tool's picker shows, which is why the saturation numbers rarely match.

Is #51a2ab a light or a dark color?

It is a mid-tone. Relative luminance is 0.3053 and perceived brightness is 56%, so black text on it reaches 7.11:1.

Should I use black or white text on #51a2ab?

Black. It scores 7.11:1 against #51a2ab, versus 2.96:1 for white — AAA at any size.

Is #51a2ab accessible on a white background?

#51a2ab on white scores 2.96:1, which fails WCAG AA at every size. Darken it to #3F7E85 to reach 4.5:1, or #306066 for 7:1.

What is the complementary color of #51a2ab?

#AB5A51 sits directly opposite on the wheel. Softer options are the split-complements #AB5175 and #AB8751, which give the same contrast with far less vibration.

What colors go well with #51a2ab?

For interface work: #F5FAFA as the surface, #C8E2E5 for borders, #4B939B for secondary text, #B04C5B as an accent and #295257 for hover and pressed states. For a palette, the analogous pair #51AB87 and #5175AB stays calm, while #AB5A51 is the loudest partner.

What is #51a2ab in CMYK for printing?

cmyk(53%, 5%, 0%, 33%). This is a screen-to-ink approximation — ask your printer for a proof before committing to a run.

Is #51a2ab warm or cool?

Cool — it scores 90 on a scale where 0 is the warmest orange and 100 the coolest azure. Nudged warmer it becomes #51AB93; nudged cooler, #4E88AD.

Which Tailwind color is closest to #51a2ab?

The cyan family — its 500 step is #06b6d4, ΔE2000 8.6 away. That is a visible difference, so define #51a2ab as a custom token rather than reaching for the built-in.

How do I use #51a2ab in Tailwind CSS?

Inline it as an arbitrary value with bg-[#51a2ab] or text-[#51a2ab], 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 #51a2ab with 50% opacity?

rgba(81, 162, 171, 0.5), or #51a2ab80 in eight-digit hex. Over white that composites to #A8D1D5; over black, #295156.

Is #51a2ab a web-safe color?

No. The nearest web-safe colour is #669999, ΔE2000 5.3 away. The palette only matters for legacy displays and some email clients now.

What does the color #51a2ab mean?

As a cyan, it reads clean, technical, fresh. Cyan reads as water, air and infrastructure: cool, hygienic, engineered. At this moderate chroma the association is present but not shouted.

What gradient works with #51a2ab?

The safest is same-hue elevation: linear-gradient(135deg, #79B9C0, #51a2ab 45%, #295257). For more colour, a short hue run to #475396 keeps it rich without turning muddy.

Work with #51a2ab in the Color Lab

Every tool opens with this colour already loaded.

Every value on this page is computed from #51a2ab at request time — conversions, contrast ratios and ΔE distances are calculated, never looked up.