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cyan · cool

#66cfac

a balanced, vivid cyan · cool · “Medium Aqua Marine”

Token name suggestion: True Teal

RGB
102, 207, 172
HSL
160°, 52%, 61%
CMYK
51, 0, 17, 19
Luminance
0.5043

#66cfac is a balanced vivid cyan, 160° on the wheel and 79/100 on the cool side. Put black text on it (11.09:1). As text it scores 1.89:1 on white — use #298265 instead. Nearest name is Medium Aqua Marine, nearest Tailwind family is teal.

hsl(160 52% 61%)rgb(102 207 172)Base step 500AAA inkCool

At a glance

Every number on this page in one read: what #66cfac is made of, how bright it looks, and which way it leans.

Hex
#66cfac
Hue
160°
cyan
Saturation
52%
vivid
Lightness
61%
balanced
Brightness
81%
HSV value
Perceived
70%
weighted brightness
Luminance
0.5043
WCAG relative
Temperature
Cool
79/100 cool
Color family
Cyan
Tone
Vivid
Best ink
Black
11.09:1
Closest name
Medium Aqua Marine
ΔE2000 0.5
Chroma
39.6
LCH, 0–130ish
OKLCH L
0.782
perceptual lightness
Tailwind
teal
500 · ΔE 9.2
Web-safe
#66CC99
nearest of 216
Where it sits
Hue160° of 360°
Saturation52%
Lightness61%
Saturation × lightness field

Left edge is grey, right edge is full chroma; top is white, bottom is black. The dot is #66cfac.

Temperature
Warm ← → Cool79% 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%
Green88%
Blue6%

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

Every format

HEX#66cfac
HEX (8-digit)#66cfacff
RGBrgb(102, 207, 172)
RGBArgba(102, 207, 172, 1)
HSLhsl(160, 52%, 61%)
HSV / HSBhsv(160, 51%, 81%)
HWBhwb(160 40% 19%)
CMYKcmyk(51%, 0%, 17%, 19%)
LABlab(76.3 -38.8 8.2)
LCHlch(76.3 39.6 168.1)
OKLCHoklch(0.782 0.111 169.2)
XYZ (D65)xyz(35.24, 50.43, 46.90)
Decimal6737836
Display P3color(display-p3 0.400 0.812 0.675)
Web-safe#66CC99

Copy-ready code

every platformclick to select
/* CSS */
color: #66cfac;
background-color: #66cfac;
/* CSS custom property */
--brand: #66cfac;
/* Tailwind (arbitrary) */
class="text-[#66cfac] bg-[#66cfac]"
/* SCSS */
$brand: #66cfac;
/* SwiftUI */
Color(red: 0.400, green: 0.812, blue: 0.675)
/* UIKit */
UIColor(red: 0.400, green: 0.812, blue: 0.675, alpha: 1)
/* Android XML */
<color name="brand">#66CFAC</color>
/* Android Compose */
Color(0xFF66CFAC)
/* Flutter */
Color(0xFF66CFAC)
/* Python / OpenCV (BGR) */
(172, 207, 102)
/* Python / PIL (RGB) */
(102, 207, 172)
/* Java AWT */
new Color(102, 207, 172)
/* .NET */
Color.FromArgb(255, 102, 207, 172)
/* OpenGL / Unity (0–1) */
(0.4000f, 0.8118f, 0.6745f, 1f)
/* LaTeX */
\definecolor{brand}{RGB}{102,207,172}
modern cssclick to select
/* mix without leaving CSS */
background: color-mix(in oklab, #66cfac 85%, white);
border-color: color-mix(in oklab, #66cfac 40%, transparent);
/* theme-aware in one line */
color: light-dark(#1E614B, #D3EEE5);
/* relative colour syntax */
--hover: hsl(from #66cfac 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: #F4FAF8;
  --brand-100: #E9F6F2;
  --brand-200: #CFEDE3;
  --brand-300: #AAE4D1;
  --brand-400: #7FD7B9;
  --brand-500: #66cfac;
  --brand-600: #3BBA90;
  --brand-700: #319B78;
  --brand-800: #277C60;
  --brand-900: #205B47;
  --brand-950: #14392C;
  --brand: #66cfac;
  --brand-ink: #000000;
  --brand-surface: #F4FAF8;
  --brand-border: #C1EBDD;
  --brand-hover: #4BC69D;
  --brand-pressed: #39B58C;
}
@media (prefers-color-scheme: dark) {
  :root {
    --brand-surface: #14241F;
    --brand-ink: #D3EEE5;
  }
}
tailwind.config.jsclick to select
theme: {
  extend: {
    colors: {
      brand: {
        50: '#F4FAF8',
        100: '#E9F6F2',
        200: '#CFEDE3',
        300: '#AAE4D1',
        400: '#7FD7B9',
        500: '#66cfac',
        600: '#3BBA90',
        700: '#319B78',
        800: '#277C60',
        900: '#205B47',
        950: '#14392C',
        DEFAULT: '#66cfac',
      },
    },
  },
}
scss mapclick to select
$brand: (
  '50': #F4FAF8,
  '100': #E9F6F2,
  '200': #CFEDE3,
  '300': #AAE4D1,
  '400': #7FD7B9,
  '500': #66cfac,
  '600': #3BBA90,
  '700': #319B78,
  '800': #277C60,
  '900': #205B47,
  '950': #14392C,
);
$brand-base: #66cfac;
$brand-ink: #000000;

@function brand($step) { @return map-get($brand, $step); }
w3c design tokens (json)click to select
{
  "color": {
    "brand": {
      "50": { "$value": "#F4FAF8", "$type": "color" },
      "100": { "$value": "#E9F6F2", "$type": "color" },
      "200": { "$value": "#CFEDE3", "$type": "color" },
      "300": { "$value": "#AAE4D1", "$type": "color" },
      "400": { "$value": "#7FD7B9", "$type": "color" },
      "500": { "$value": "#66cfac", "$type": "color" },
      "600": { "$value": "#3BBA90", "$type": "color" },
      "700": { "$value": "#319B78", "$type": "color" },
      "800": { "$value": "#277C60", "$type": "color" },
      "900": { "$value": "#205B47", "$type": "color" },
      "950": { "$value": "#14392C", "$type": "color" }
    },
    "brandInk": { "$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 #66cfac · 11.09:1
Use #000000AAA at every size.
Aa
12px
Aa
16px
Aa
24px
Aa
White text · 1.89:1
AA fail · AA large fail · AAA fail
Aa
Black text · 11.09:1 · recommended
AA pass · AA large pass · AAA pass
Reading the other direction: #66cfac as text scores 1.89:1 on white and 11.09:1 on black.
Best tinted ink on it, if plain black or white feels flat: #1E614B at 3.87:1.

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
#298265 · 4.69:1
AA on white−27% L
#298265
The quick fox
#1F634D · 7.12:1
AAA on white−35% L
#1F634D
The quick fox
#66cfac · 11.09:1
AA on blackalready passes
#66cfac
The quick fox
#66cfac · 11.09:1
AAA on blackalready passes
#66cfac

Large text — 24px regular or 18.66px bold and above — only needs 3:1, so #34A580 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
#66cfac on white: 1.89:1
AA ✗ fail · AA-large · AAA
Aa
#66cfac on black: 11.09:1
AA ✓ pass · AA-large · AAA
Against the neutral ladder

Contrast is symmetric, so each row covers both directions: #66cfac as text on that neutral, and that neutral as text on #66cfac.

NeutralRatioBoth directions
White1.89:1AaAa
Slate 501.81:1AaAa
Slate 1001.73:1AaAa
Slate 2001.54:1AaAa
Slate 3001.28:1AaAa
Slate 4001.35:1AaAa
Slate 5002.51:1AaAa
Slate 6004.00:1AaAa
Slate 7005.47:1AaAa
Slate 8007.72:1AaAa
Slate 9009.42:1AaAa
Black11.09:1AaAa
Colour vision deficiency
true color
protanopia · #CAC3AA
deuteranopia · #BAB7AE
tritanopia · #3CD0C5

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. #66cfac is pinned to step 500; the rest hold its hue and let saturation ease off at the extremes so the pale end never turns neon.

#F4FAF8
#E9F6F2
#CFEDE3
#AAE4D1
#7FD7B9
#66cfac
#3BBA90
#319B78
#277C60
#205B47
#14392C
Base = 500Lightest = 50 · #F4FAF8Darkest = 950 · #14392CText 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 0.028 169.2);
  --brand-100: oklch(0.94 0.044 169.2);
  --brand-200: oklch(0.88 0.067 169.2);
  --brand-300: oklch(0.80 0.087 169.2);
  --brand-400: oklch(0.72 0.102 169.2);
  --brand-500: oklch(0.64 0.111 169.2);
  --brand-600: oklch(0.56 0.111 169.2);
  --brand-700: oklch(0.48 0.104 169.2);
  --brand-800: oklch(0.40 0.093 169.2);
  --brand-900: oklch(0.32 0.078 169.2);
  --brand-950: oklch(0.24 0.061 169.2);
}

Colors that work with #66cfac

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#F4FAF8
Tinted page background
Border#C1EBDD
Hairlines and dividers
Muted text#4B9B80
Captions on the surface
Accent#D362A4
Second voice, not a rival
Dark variant#1E614B
Hover, pressed, headers
Light variant#ECF9F4
Selected rows, tints
Dark surface#14241F
Dark-mode background
Hover#4BC69D
One step down in lightness
Pressed#39B58C
Two steps down
Disabled#C9DCD6
Chroma pulled out
Focus ring#6DDDB7
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 #66cfac

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
  • Brand accents, badges and data highlights
  • Chart series and data categories
Use with care
  • Text of any size on white — fails WCAG AA
  • Full-page backgrounds — tiring over long sessions
  • 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 #1E614B
Safe as a 1px border on white
No — use #34A580

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 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-high
  • Weight39/100
  • 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#CF6689
Analogous left#66CF78
Analogous right#66BDCF
Split-complement 1#CF66BD
Split-complement 2#CF7866
Triadic 1#AC66CF
Triadic 2#CFAC66
Tetradic#7866CF
On the wheel
Base+30°−30°+120°+240°+180°160°

#66cfac sits at 160°. Every dot is a harmony position and links to its own page in the table alongside.

RGB percentages

Red40.0%
Green81.2%
Blue67.5%
R · 0–255
102
0x66
G · 0–255
207
0xcf
B · 0–255
172
0xac

CMYK percentages

Cyan50.7%
Magenta0.0%
Yellow16.9%
Key (black)18.8%

Total ink coverage is 86%. Most commercial presses cap around 300% — above that, sheets stop drying properly.

Color previews

#66cfac text on a black background

contrast 11.09:1

Card sample

#66cfac text on a white background

contrast 1.89:1

Card sample

#66cfac on grey

1.73:1

#66cfac on its own surface

1.79:1

#66cfac on its dark surface

8.52:1

CSS3 live lab

Text font color

The quick brown fox

color: #66cfac;
Background color
Panel with #66cfac background
background-color: #66cfac;
Text shadow — hex

Glowing headline

text-shadow: 2px 2px 8px #66cfac;
Text shadow — RGB

Soft neon halo

text-shadow: 0 0 14px rgba(102, 207, 172, 0.45);
Div box shadow
Elevated card
box-shadow: 0 12px 32px -8px rgba(102, 207, 172, 0.45);
Border & gradient
Gradient panel
border: 3px solid #66cfac;
background: linear-gradient(135deg, #66cfac, #66ACCF);
Gradient text

Gradient headline

background: linear-gradient(90deg, #66cfac, #6692CF);
-webkit-background-clip: text;
color: transparent;
Focus ring
Focused control
outline: 2px solid #66cfac;
outline-offset: 3px;
Underline & caret

Marked up text

text-decoration-color: #66cfac;
caret-color: #66cfac;
Left rule
Pull quote or callout
border-left: 4px solid #66cfac;
Ring + tint
Selected chip
background: #ECF9F4;
box-shadow: inset 0 0 0 2px #66cfac;
Conic badge
68%
background: conic-gradient(#66cfac 68%, #e2e8f0 0);

Transparency

What each alpha value actually composites to. The top row is #66cfac 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, 207, 172, 0.5)
rgb(102 207 172 / 50%)
#66cfac80
hsl(160 52% 61% / 50%)
color-mix(in srgb, #66cfac 50%, transparent)
Alpha8-digit hexFlat on white
10%#66cfac1a#F0FAF7
20%#66cfac33#E0F5EE
40%#66cfac66#C2ECDE
60%#66cfac99#A3E2CD
80%#66cfaccc#85D9BD

Gradients from #66cfac

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, #95DEC5, #66cfac 45%, #1E614B);
Duotone
A short hue run reads richer than a flat fill
background: linear-gradient(120deg, #66cfac, #4F95C8);
Complement sweep
Loud — keep it behind large type only
background: linear-gradient(90deg, #66cfac, #CF6689);
Spotlight
Hero panels and app headers
background: radial-gradient(120% 120% at 20% 0%, #ACE5D2 0%, #66cfac 45%, #1E614B 100%);
Soft wash
Section backgrounds that stay readable
background: linear-gradient(180deg, #F4FAF8, #ffffff);
Mesh
Ambient background, no image weight
background: radial-gradient(60% 60% at 15% 20%, #8DDB93 0%, transparent 60%), radial-gradient(55% 55% at 85% 15%, #7DC0D6 0%, transparent 60%), radial-gradient(70% 70% at 50% 95%, #1E614B 0%, transparent 65%), #66cfac;

Monochromatic scale

Palettes built from #66cfac

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.

#66cfac 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 11.09:1.

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.

#66cfac, answered

What color is #66cfac?

#66cfac is a balanced vivid cyan — the CSS keyword Medium Aqua Marine. It sits at 160° on the hue wheel with 52% saturation and 61% lightness, which reads as cool.

What is the RGB value of #66cfac?

rgb(102, 207, 172) — 102 red, 207 green and 172 blue out of 255, or 40% / 81.2% / 67.5% by channel.

What is #66cfac in HSL and HSV?

hsl(160, 52%, 61%) and hsv(160, 51%, 81%). HSL is what CSS takes; HSV is what your design tool's picker shows, which is why the saturation numbers rarely match.

Is #66cfac a light or a dark color?

It is a light color. Relative luminance is 0.5043 and perceived brightness is 70%, so black text on it reaches 11.09:1.

Should I use black or white text on #66cfac?

Black. It scores 11.09:1 against #66cfac, versus 1.89:1 for white — AAA at any size.

Is #66cfac accessible on a white background?

#66cfac on white scores 1.89:1, which fails WCAG AA at every size. Darken it to #298265 to reach 4.5:1, or #1F634D for 7:1.

What is the complementary color of #66cfac?

#CF6689 sits directly opposite on the wheel. Softer options are the split-complements #CF66BD and #CF7866, which give the same contrast with far less vibration.

What colors go well with #66cfac?

For interface work: #F4FAF8 as the surface, #C1EBDD for borders, #4B9B80 for secondary text, #D362A4 as an accent and #1E614B for hover and pressed states. For a palette, the analogous pair #66CF78 and #66BDCF stays calm, while #CF6689 is the loudest partner.

What is #66cfac in CMYK for printing?

cmyk(51%, 0%, 17%, 19%). This is a screen-to-ink approximation — ask your printer for a proof before committing to a run.

Is #66cfac warm or cool?

Cool — it scores 79 on a scale where 0 is the warmest orange and 100 the coolest azure. Nudged warmer it becomes #66CF86; nudged cooler, #64CDD1.

Which Tailwind color is closest to #66cfac?

The teal family — its 500 step is #14b8a6, ΔE2000 9.2 away. That is a visible difference, so define #66cfac as a custom token rather than reaching for the built-in.

How do I use #66cfac in Tailwind CSS?

Inline it as an arbitrary value with bg-[#66cfac] or text-[#66cfac], 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 #66cfac with 50% opacity?

rgba(102, 207, 172, 0.5), or #66cfac80 in eight-digit hex. Over white that composites to #B3E7D6; over black, #336856.

Is #66cfac a web-safe color?

No. The nearest web-safe colour is #66CC99, ΔE2000 4.5 away. The palette only matters for legacy displays and some email clients now.

What does the color #66cfac 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 #66cfac?

The safest is same-hue elevation: linear-gradient(135deg, #95DEC5, #66cfac 45%, #1E614B). For more colour, a short hue run to #4F95C8 keeps it rich without turning muddy.

Work with #66cfac in the Color Lab

Every tool opens with this colour already loaded.

Every value on this page is computed from #66cfac at request time — conversions, contrast ratios and ΔE distances are calculated, never looked up.