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cyan · cool

#37bfdf

a balanced, vivid cyan · cool · closest name: Sky Blue

Token name suggestion: Atlas Teal

RGB
55, 191, 223
HSL
191°, 72%, 55%
CMYK
75, 14, 0, 13
Luminance
0.4340

#37bfdf is a balanced vivid cyan, 191° on the wheel and 92/100 on the cool side. Put black text on it (9.68:1). As text it scores 2.17:1 on white — use #187F98 instead. Nearest name is Sky Blue, nearest Tailwind family is cyan.

hsl(191 72% 55%)rgb(55 191 223)Base step 500AAA inkCool

At a glance

Every number on this page in one read: what #37bfdf is made of, how bright it looks, and which way it leans.

Hex
#37bfdf
Hue
191°
cyan
Saturation
72%
vivid
Lightness
55%
balanced
Brightness
87%
HSV value
Perceived
66%
weighted brightness
Luminance
0.4340
WCAG relative
Temperature
Cool
92/100 cool
Color family
Cyan
Tone
Vivid
Best ink
Black
9.68:1
Closest name
Sky Blue
ΔE2000 7.6
Chroma
36.5
LCH, 0–130ish
OKLCH L
0.747
perceptual lightness
Tailwind
cyan
500 · ΔE 3
Web-safe
#33CCCC
nearest of 216
Where it sits
Hue191° of 360°
Saturation72%
Lightness55%
Saturation × lightness field

Left edge is grey, right edge is full chroma; top is white, bottom is black. The dot is #37bfdf.

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
Red2%
Green86%
Blue12%

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

Every format

HEX#37bfdf
HEX (8-digit)#37bfdfff
RGBrgb(55, 191, 223)
RGBArgba(55, 191, 223, 1)
HSLhsl(191, 72%, 55%)
HSV / HSBhsv(191, 75%, 87%)
HWBhwb(191 22% 13%)
CMYKcmyk(75%, 14%, 0%, 13%)
LABlab(71.8 -25.3 -26.3)
LCHlch(71.8 36.5 226.1)
OKLCHoklch(0.747 0.120 217.6)
XYZ (D65)xyz(33.52, 43.40, 76.41)
Decimal3653599
Display P3color(display-p3 0.216 0.749 0.875)
Web-safe#33CCCC

Copy-ready code

every platformclick to select
/* CSS */
color: #37bfdf;
background-color: #37bfdf;
/* CSS custom property */
--brand: #37bfdf;
/* Tailwind (arbitrary) */
class="text-[#37bfdf] bg-[#37bfdf]"
/* SCSS */
$brand: #37bfdf;
/* SwiftUI */
Color(red: 0.216, green: 0.749, blue: 0.875)
/* UIKit */
UIColor(red: 0.216, green: 0.749, blue: 0.875, alpha: 1)
/* Android XML */
<color name="brand">#37BFDF</color>
/* Android Compose */
Color(0xFF37BFDF)
/* Flutter */
Color(0xFF37BFDF)
/* Python / OpenCV (BGR) */
(223, 191, 55)
/* Python / PIL (RGB) */
(55, 191, 223)
/* Java AWT */
new Color(55, 191, 223)
/* .NET */
Color.FromArgb(255, 55, 191, 223)
/* OpenGL / Unity (0–1) */
(0.2157f, 0.7490f, 0.8745f, 1f)
/* LaTeX */
\definecolor{brand}{RGB}{55,191,223}
modern cssclick to select
/* mix without leaving CSS */
background: color-mix(in oklab, #37bfdf 85%, white);
border-color: color-mix(in oklab, #37bfdf 40%, transparent);
/* theme-aware in one line */
color: light-dark(#125C6E, #D3E9EE);
/* relative colour syntax */
--hover: hsl(from #37bfdf 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: #F3FAFC;
  --brand-100: #E7F5F8;
  --brand-200: #C9EBF3;
  --brand-300: #9EE0F0;
  --brand-400: #6ED1E8;
  --brand-500: #37bfdf;
  --brand-600: #22B1D3;
  --brand-700: #1C94B0;
  --brand-800: #17768D;
  --brand-900: #145666;
  --brand-950: #0D3640;
  --brand: #37bfdf;
  --brand-ink: #000000;
  --brand-surface: #F4F9FA;
  --brand-border: #C0E4ED;
  --brand-hover: #21AFD1;
  --brand-pressed: #1D96B2;
}
@media (prefers-color-scheme: dark) {
  :root {
    --brand-surface: #142124;
    --brand-ink: #D3E9EE;
  }
}
tailwind.config.jsclick to select
theme: {
  extend: {
    colors: {
      brand: {
        50: '#F3FAFC',
        100: '#E7F5F8',
        200: '#C9EBF3',
        300: '#9EE0F0',
        400: '#6ED1E8',
        500: '#37bfdf',
        600: '#22B1D3',
        700: '#1C94B0',
        800: '#17768D',
        900: '#145666',
        950: '#0D3640',
        DEFAULT: '#37bfdf',
      },
    },
  },
}
scss mapclick to select
$brand: (
  '50': #F3FAFC,
  '100': #E7F5F8,
  '200': #C9EBF3,
  '300': #9EE0F0,
  '400': #6ED1E8,
  '500': #37bfdf,
  '600': #22B1D3,
  '700': #1C94B0,
  '800': #17768D,
  '900': #145666,
  '950': #0D3640,
);
$brand-base: #37bfdf;
$brand-ink: #000000;

@function brand($step) { @return map-get($brand, $step); }
w3c design tokens (json)click to select
{
  "color": {
    "brand": {
      "50": { "$value": "#F3FAFC", "$type": "color" },
      "100": { "$value": "#E7F5F8", "$type": "color" },
      "200": { "$value": "#C9EBF3", "$type": "color" },
      "300": { "$value": "#9EE0F0", "$type": "color" },
      "400": { "$value": "#6ED1E8", "$type": "color" },
      "500": { "$value": "#37bfdf", "$type": "color" },
      "600": { "$value": "#22B1D3", "$type": "color" },
      "700": { "$value": "#1C94B0", "$type": "color" },
      "800": { "$value": "#17768D", "$type": "color" },
      "900": { "$value": "#145666", "$type": "color" },
      "950": { "$value": "#0D3640", "$type": "color" }
    },
    "brandInk": { "$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 #37bfdf · 9.68:1
Use #000000AAA at every size.
Aa
12px
Aa
16px
Aa
24px
Aa
White text · 2.17:1
AA fail · AA large fail · AAA fail
Aa
Black text · 9.68:1 · recommended
AA pass · AA large pass · AAA pass
Reading the other direction: #37bfdf as text scores 2.17:1 on white and 9.68:1 on black.
Best tinted ink on it, if plain black or white feels flat: #125C6E at 3.48:1.

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
#187F98 · 4.64:1
AA on white−20% L
#187F98
The quick fox
#125E70 · 7.34:1
AAA on white−29% L
#125E70
The quick fox
#37bfdf · 9.68:1
AA on blackalready passes
#37bfdf
The quick fox
#37bfdf · 9.68:1
AAA on blackalready passes
#37bfdf

Large text — 24px regular or 18.66px bold and above — only needs 3:1, so #1FA1BF 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
#37bfdf on white: 2.17:1
AA ✗ fail · AA-large · AAA
Aa
#37bfdf on black: 9.68:1
AA ✓ pass · AA-large · AAA
Against the neutral ladder

Contrast is symmetric, so each row covers both directions: #37bfdf as text on that neutral, and that neutral as text on #37bfdf.

NeutralRatioBoth directions
White2.17:1AaAa
Slate 502.07:1AaAa
Slate 1001.98:1AaAa
Slate 2001.76:1AaAa
Slate 3001.46:1AaAa
Slate 4001.18:1AaAa
Slate 5002.19:1AaAa
Slate 6003.49:1AaAa
Slate 7004.77:1AaAa
Slate 8006.74:1AaAa
Slate 9008.23:1AaAa
Black9.68:1AaAa
Colour vision deficiency
true color
protanopia · #AAB9E1
deuteranopia · #94A9DF
tritanopia · #00CAC9

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. #37bfdf 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.

#F3FAFC
#E7F5F8
#C9EBF3
#9EE0F0
#6ED1E8
#37bfdf
#22B1D3
#1C94B0
#17768D
#145666
#0D3640
Base = 500Lightest = 50 · #F3FAFCDarkest = 950 · #0D3640Text 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 0.030 217.6);
  --brand-100: oklch(0.94 0.048 217.6);
  --brand-200: oklch(0.88 0.072 217.6);
  --brand-300: oklch(0.80 0.094 217.6);
  --brand-400: oklch(0.72 0.111 217.6);
  --brand-500: oklch(0.64 0.120 217.6);
  --brand-600: oklch(0.56 0.120 217.6);
  --brand-700: oklch(0.48 0.113 217.6);
  --brand-800: oklch(0.40 0.101 217.6);
  --brand-900: oklch(0.32 0.084 217.6);
  --brand-950: oklch(0.24 0.066 217.6);
}

Colors that work with #37bfdf

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#C0E4ED
Hairlines and dividers
Muted text#4B8C9B
Captions on the surface
Accent#E4323D
Second voice, not a rival
Dark variant#125C6E
Hover, pressed, headers
Light variant#E9F8FB
Selected rows, tints
Dark surface#142124
Dark-mode background
Hover#21AFD1
One step down in lightness
Pressed#1D96B2
Two steps down
Disabled#B6CBD0
Chroma pulled out
Focus ring#3ECBEC
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 #37bfdf

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 #125C6E
Safe as a 1px border on white
No — use #1FA1BF

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
  • Weight46/100
  • 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#DF5737
Analogous left#37DFAB
Analogous right#376BDF
Split-complement 1#DF376B
Split-complement 2#DFAB37
Triadic 1#DF37BF
Triadic 2#BFDF37
Tetradic#AB37DF
On the wheel
Base+30°−30°+120°+240°+180°191°

#37bfdf sits at 191°. Every dot is a harmony position and links to its own page in the table alongside.

RGB percentages

Red21.6%
Green74.9%
Blue87.5%
R · 0–255
55
0x37
G · 0–255
191
0xbf
B · 0–255
223
0xdf

CMYK percentages

Cyan75.3%
Magenta14.3%
Yellow0.0%
Key (black)12.5%

Total ink coverage is 102%. Most commercial presses cap around 300% — above that, sheets stop drying properly.

Color previews

#37bfdf text on a black background

contrast 9.68:1

Card sample

#37bfdf text on a white background

contrast 2.17:1

Card sample

#37bfdf on grey

1.98:1

#37bfdf on its own surface

2.04:1

#37bfdf on its dark surface

7.61:1

CSS3 live lab

Text font color

The quick brown fox

color: #37bfdf;
Background color
Panel with #37bfdf background
background-color: #37bfdf;
Text shadow — hex

Glowing headline

text-shadow: 2px 2px 8px #37bfdf;
Text shadow — RGB

Soft neon halo

text-shadow: 0 0 14px rgba(55, 191, 223, 0.45);
Div box shadow
Elevated card
box-shadow: 0 12px 32px -8px rgba(55, 191, 223, 0.45);
Border & gradient
Gradient panel
border: 3px solid #37bfdf;
background: linear-gradient(135deg, #37bfdf, #374FDF);
Gradient text

Gradient headline

background: linear-gradient(90deg, #37bfdf, #4937DF);
-webkit-background-clip: text;
color: transparent;
Focus ring
Focused control
outline: 2px solid #37bfdf;
outline-offset: 3px;
Underline & caret

Marked up text

text-decoration-color: #37bfdf;
caret-color: #37bfdf;
Left rule
Pull quote or callout
border-left: 4px solid #37bfdf;
Ring + tint
Selected chip
background: #E9F8FB;
box-shadow: inset 0 0 0 2px #37bfdf;
Conic badge
68%
background: conic-gradient(#37bfdf 68%, #e2e8f0 0);

Transparency

What each alpha value actually composites to. The top row is #37bfdf 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(55, 191, 223, 0.5)
rgb(55 191 223 / 50%)
#37bfdf80
hsl(191 72% 55% / 50%)
color-mix(in srgb, #37bfdf 50%, transparent)
Alpha8-digit hexFlat on white
10%#37bfdf1a#EBF9FC
20%#37bfdf33#D7F2F9
40%#37bfdf66#AFE5F2
60%#37bfdf99#87D9EC
80%#37bfdfcc#5FCCE5

Gradients from #37bfdf

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, #6CD0E7, #37bfdf 45%, #125C6E);
Duotone
A short hue run reads richer than a flat fill
background: linear-gradient(120deg, #37bfdf, #222DD5);
Complement sweep
Loud — keep it behind large type only
background: linear-gradient(90deg, #37bfdf, #DF5737);
Spotlight
Hero panels and app headers
background: radial-gradient(120% 120% at 20% 0%, #86D8EC 0%, #37bfdf 45%, #125C6E 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%, #63E6B2 0%, transparent 60%), radial-gradient(55% 55% at 85% 15%, #5172E3 0%, transparent 60%), radial-gradient(70% 70% at 50% 95%, #125C6E 0%, transparent 65%), #37bfdf;

Monochromatic scale

Palettes built from #37bfdf

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.

#37bfdf 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 9.68:1.

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.

#37bfdf, answered

What color is #37bfdf?

#37bfdf is a balanced vivid cyan, closest to Sky Blue (ΔE2000 7.6). It sits at 191° on the hue wheel with 72% saturation and 55% lightness, which reads as cool.

What is the RGB value of #37bfdf?

rgb(55, 191, 223) — 55 red, 191 green and 223 blue out of 255, or 21.6% / 74.9% / 87.5% by channel.

What is #37bfdf in HSL and HSV?

hsl(191, 72%, 55%) and hsv(191, 75%, 87%). HSL is what CSS takes; HSV is what your design tool's picker shows, which is why the saturation numbers rarely match.

Is #37bfdf a light or a dark color?

It is a mid-tone. Relative luminance is 0.4340 and perceived brightness is 66%, so black text on it reaches 9.68:1.

Should I use black or white text on #37bfdf?

Black. It scores 9.68:1 against #37bfdf, versus 2.17:1 for white — AAA at any size.

Is #37bfdf accessible on a white background?

#37bfdf on white scores 2.17:1, which fails WCAG AA at every size. Darken it to #187F98 to reach 4.5:1, or #125E70 for 7:1.

What is the complementary color of #37bfdf?

#DF5737 sits directly opposite on the wheel. Softer options are the split-complements #DF376B and #DFAB37, which give the same contrast with far less vibration.

What colors go well with #37bfdf?

For interface work: #F4F9FA as the surface, #C0E4ED for borders, #4B8C9B for secondary text, #E4323D as an accent and #125C6E for hover and pressed states. For a palette, the analogous pair #37DFAB and #376BDF stays calm, while #DF5737 is the loudest partner.

What is #37bfdf in CMYK for printing?

cmyk(75%, 14%, 0%, 13%). This is a screen-to-ink approximation — ask your printer for a proof before committing to a run.

Is #37bfdf 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 #37DFC1; nudged cooler, #35A1E1.

Which Tailwind color is closest to #37bfdf?

The cyan family — its 500 step is #06b6d4, ΔE2000 3 away. That is a visible difference, so define #37bfdf as a custom token rather than reaching for the built-in.

How do I use #37bfdf in Tailwind CSS?

Inline it as an arbitrary value with bg-[#37bfdf] or text-[#37bfdf], 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 #37bfdf with 50% opacity?

rgba(55, 191, 223, 0.5), or #37bfdf80 in eight-digit hex. Over white that composites to #9BDFEF; over black, #1C6070.

Is #37bfdf a web-safe color?

No. The nearest web-safe colour is #33CCCC, ΔE2000 11.6 away. The palette only matters for legacy displays and some email clients now.

What does the color #37bfdf 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 #37bfdf?

The safest is same-hue elevation: linear-gradient(135deg, #6CD0E7, #37bfdf 45%, #125C6E). For more colour, a short hue run to #222DD5 keeps it rich without turning muddy.

Work with #37bfdf in the Color Lab

Every tool opens with this colour already loaded.

Every value on this page is computed from #37bfdf at request time — conversions, contrast ratios and ΔE distances are calculated, never looked up.