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blue · cool

#5bbcee

a balanced, electric blue · cool · closest name: Deep Sky Blue

Token name suggestion: Signal Harbour

RGB
91, 188, 238
HSL
200°, 81%, 65%
CMYK
62, 21, 0, 7
Luminance
0.4436

#5bbcee is a balanced electric blue, 200° on the wheel and 96/100 on the cool side. Put black text on it (9.87:1). As text it scores 2.13:1 on white — use #127CB2 instead. Nearest name is Deep Sky Blue, nearest Tailwind family is sky.

hsl(200 81% 65%)rgb(91 188 238)Base step 400AAA inkCool

At a glance

Every number on this page in one read: what #5bbcee is made of, how bright it looks, and which way it leans.

Hex
#5bbcee
Hue
200°
blue
Saturation
81%
electric
Lightness
65%
balanced
Brightness
93%
HSV value
Perceived
68%
weighted brightness
Luminance
0.4436
WCAG relative
Temperature
Cool
96/100 cool
Color family
Blue
Tone
Electric
Best ink
Black
9.87:1
Closest name
Deep Sky Blue
ΔE2000 3.5
Chroma
36.1
LCH, 0–130ish
OKLCH L
0.757
perceptual lightness
Tailwind
sky
500 · ΔE 7.5
Web-safe
#66CCFF
nearest of 216
Where it sits
Hue200° of 360°
Saturation81%
Lightness65%
Saturation × lightness field

Left edge is grey, right edge is full chroma; top is white, bottom is black. The dot is #5bbcee.

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
Red5%
Green81%
Blue14%

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

Every format

HEX#5bbcee
HEX (8-digit)#5bbceeff
RGBrgb(91, 188, 238)
RGBArgba(91, 188, 238, 1)
HSLhsl(200, 81%, 65%)
HSV / HSBhsv(200, 62%, 93%)
HWBhwb(200 36% 7%)
CMYKcmyk(62%, 21%, 0%, 7%)
LABlab(72.5 -13.9 -33.4)
LCHlch(72.5 36.1 247.4)
OKLCHoklch(0.757 0.116 233.7)
XYZ (D65)xyz(37.72, 44.36, 87.45)
Decimal6012142
Display P3color(display-p3 0.357 0.737 0.933)
Web-safe#66CCFF

Copy-ready code

every platformclick to select
/* CSS */
color: #5bbcee;
background-color: #5bbcee;
/* CSS custom property */
--brand: #5bbcee;
/* Tailwind (arbitrary) */
class="text-[#5bbcee] bg-[#5bbcee]"
/* SCSS */
$brand: #5bbcee;
/* SwiftUI */
Color(red: 0.357, green: 0.737, blue: 0.933)
/* UIKit */
UIColor(red: 0.357, green: 0.737, blue: 0.933, alpha: 1)
/* Android XML */
<color name="brand">#5BBCEE</color>
/* Android Compose */
Color(0xFF5BBCEE)
/* Flutter */
Color(0xFF5BBCEE)
/* Python / OpenCV (BGR) */
(238, 188, 91)
/* Python / PIL (RGB) */
(91, 188, 238)
/* Java AWT */
new Color(91, 188, 238)
/* .NET */
Color.FromArgb(255, 91, 188, 238)
/* OpenGL / Unity (0–1) */
(0.3569f, 0.7373f, 0.9333f, 1f)
/* LaTeX */
\definecolor{brand}{RGB}{91,188,238}
modern cssclick to select
/* mix without leaving CSS */
background: color-mix(in oklab, #5bbcee 85%, white);
border-color: color-mix(in oklab, #5bbcee 40%, transparent);
/* theme-aware in one line */
color: light-dark(#0C5074, #D3E5EE);
/* relative colour syntax */
--hover: hsl(from #5bbcee 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: #E6F3F9;
  --brand-200: #C6E5F6;
  --brand-300: #99D5F4;
  --brand-400: #5bbcee;
  --brand-500: #34ACEA;
  --brand-600: #179ADE;
  --brand-700: #1381B9;
  --brand-800: #0F6794;
  --brand-900: #0F4C6B;
  --brand-950: #0A2F43;
  --brand: #5bbcee;
  --brand-ink: #000000;
  --brand-surface: #F4F8FA;
  --brand-border: #C0DDED;
  --brand-hover: #3BAFEB;
  --brand-pressed: #1AA2E7;
}
@media (prefers-color-scheme: dark) {
  :root {
    --brand-surface: #141F24;
    --brand-ink: #D3E5EE;
  }
}
tailwind.config.jsclick to select
theme: {
  extend: {
    colors: {
      brand: {
        50: '#F3F9FC',
        100: '#E6F3F9',
        200: '#C6E5F6',
        300: '#99D5F4',
        400: '#5bbcee',
        500: '#34ACEA',
        600: '#179ADE',
        700: '#1381B9',
        800: '#0F6794',
        900: '#0F4C6B',
        950: '#0A2F43',
        DEFAULT: '#5bbcee',
      },
    },
  },
}
scss mapclick to select
$brand: (
  '50': #F3F9FC,
  '100': #E6F3F9,
  '200': #C6E5F6,
  '300': #99D5F4,
  '400': #5bbcee,
  '500': #34ACEA,
  '600': #179ADE,
  '700': #1381B9,
  '800': #0F6794,
  '900': #0F4C6B,
  '950': #0A2F43,
);
$brand-base: #5bbcee;
$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": "#E6F3F9", "$type": "color" },
      "200": { "$value": "#C6E5F6", "$type": "color" },
      "300": { "$value": "#99D5F4", "$type": "color" },
      "400": { "$value": "#5bbcee", "$type": "color" },
      "500": { "$value": "#34ACEA", "$type": "color" },
      "600": { "$value": "#179ADE", "$type": "color" },
      "700": { "$value": "#1381B9", "$type": "color" },
      "800": { "$value": "#0F6794", "$type": "color" },
      "900": { "$value": "#0F4C6B", "$type": "color" },
      "950": { "$value": "#0A2F43", "$type": "color" }
    },
    "brandInk": { "$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 #5bbcee · 9.87:1
Use #000000AAA at every size.
Aa
12px
Aa
16px
Aa
24px
Aa
White text · 2.13:1
AA fail · AA large fail · AAA fail
Aa
Black text · 9.87:1 · recommended
AA pass · AA large pass · AAA pass
Reading the other direction: #5bbcee as text scores 2.13:1 on white and 9.87:1 on black.
Best tinted ink on it, if plain black or white feels flat: #0C5074 at 4.09:1.

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
#127CB2 · 4.61:1
AA on white−26% L
#127CB2
The quick fox
#0E5C84 · 7.28:1
AAA on white−36% L
#0E5C84
The quick fox
#5bbcee · 9.87:1
AA on blackalready passes
#5bbcee
The quick fox
#5bbcee · 9.87:1
AAA on blackalready passes
#5bbcee

Large text — 24px regular or 18.66px bold and above — only needs 3:1, so #179CE0 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
#5bbcee on white: 2.13:1
AA ✗ fail · AA-large · AAA
Aa
#5bbcee on black: 9.87:1
AA ✓ pass · AA-large · AAA
Against the neutral ladder

Contrast is symmetric, so each row covers both directions: #5bbcee as text on that neutral, and that neutral as text on #5bbcee.

NeutralRatioBoth directions
White2.13:1AaAa
Slate 502.03:1AaAa
Slate 1001.94:1AaAa
Slate 2001.73:1AaAa
Slate 3001.43:1AaAa
Slate 4001.21:1AaAa
Slate 5002.24:1AaAa
Slate 6003.56:1AaAa
Slate 7004.87:1AaAa
Slate 8006.88:1AaAa
Slate 9008.39:1AaAa
Black9.87:1AaAa
Colour vision deficiency
true color
protanopia · #A4BAF0
deuteranopia · #8FABED
tritanopia · #00C9CD

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. #5bbcee is pinned to step 400; the rest hold its hue and let saturation ease off at the extremes so the pale end never turns neon.

#F3F9FC
#E6F3F9
#C6E5F6
#99D5F4
#5bbcee
#34ACEA
#179ADE
#1381B9
#0F6794
#0F4C6B
#0A2F43
Base = 400Lightest = 50 · #F3F9FCDarkest = 950 · #0A2F43Text 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 0.029 233.7);
  --brand-100: oklch(0.94 0.046 233.7);
  --brand-200: oklch(0.88 0.070 233.7);
  --brand-300: oklch(0.80 0.090 233.7);
  --brand-400: oklch(0.72 0.107 233.7);
  --brand-500: oklch(0.64 0.116 233.7);
  --brand-600: oklch(0.56 0.116 233.7);
  --brand-700: oklch(0.48 0.109 233.7);
  --brand-800: oklch(0.40 0.097 233.7);
  --brand-900: oklch(0.32 0.081 233.7);
  --brand-950: oklch(0.24 0.064 233.7);
}

Colors that work with #5bbcee

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#C0DDED
Hairlines and dividers
Muted text#4B809B
Captions on the surface
Accent#BD1E0F
Second voice, not a rival
Dark variant#0C5074
Hover, pressed, headers
Light variant#E8F6FD
Selected rows, tints
Dark surface#141F24
Dark-mode background
Hover#3BAFEB
One step down in lightness
Pressed#1AA2E7
Two steps down
Disabled#D5DFE4
Chroma pulled out
Focus ring#65C6F8
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 #5bbcee

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
  • 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 #0C5074
Safe as a 1px border on white
No — use #179CE0

Meaning and mood

What a colour in this family tends to signal, and how this particular chroma and lightness change the reading.

trustedcalmcompetentcorporate

The default of institutions for a reason: blue is read as stable and safe across nearly every culture that has been surveyed.

At this chroma the association is amplified — it will dominate anything placed beside it, so give it space and use it sparingly. The mid lightness keeps it versatile in both themes.

Worth knowing

It is also the most crowded hue on the web. Distinctiveness has to come from your other choices.

Reads as
  • FormalityLow
  • EnergyHigh
  • Weight36/100
  • 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#EE8D5B
Analogous left#5BEED6
Analogous right#5B72EE
Split-complement 1#EE5B72
Split-complement 2#EED65B
Triadic 1#EE5BBC
Triadic 2#BCEE5B
Tetradic#D65BEE
On the wheel
Base+30°−30°+120°+240°+180°200°

#5bbcee sits at 200°. Every dot is a harmony position and links to its own page in the table alongside.

RGB percentages

Red35.7%
Green73.7%
Blue93.3%
R · 0–255
91
0x5b
G · 0–255
188
0xbc
B · 0–255
238
0xee

CMYK percentages

Cyan61.8%
Magenta21.0%
Yellow0.0%
Key (black)6.7%

Total ink coverage is 90%. Most commercial presses cap around 300% — above that, sheets stop drying properly.

Color previews

#5bbcee text on a black background

contrast 9.87:1

Card sample

#5bbcee text on a white background

contrast 2.13:1

Card sample

#5bbcee on grey

1.94:1

#5bbcee on its own surface

1.99:1

#5bbcee on its dark surface

7.89:1

CSS3 live lab

Text font color

The quick brown fox

color: #5bbcee;
Background color
Panel with #5bbcee background
background-color: #5bbcee;
Text shadow — hex

Glowing headline

text-shadow: 2px 2px 8px #5bbcee;
Text shadow — RGB

Soft neon halo

text-shadow: 0 0 14px rgba(91, 188, 238, 0.45);
Div box shadow
Elevated card
box-shadow: 0 12px 32px -8px rgba(91, 188, 238, 0.45);
Border & gradient
Gradient panel
border: 3px solid #5bbcee;
background: linear-gradient(135deg, #5bbcee, #5C5BEE);
Gradient text

Gradient headline

background: linear-gradient(90deg, #5bbcee, #815BEE);
-webkit-background-clip: text;
color: transparent;
Focus ring
Focused control
outline: 2px solid #5bbcee;
outline-offset: 3px;
Underline & caret

Marked up text

text-decoration-color: #5bbcee;
caret-color: #5bbcee;
Left rule
Pull quote or callout
border-left: 4px solid #5bbcee;
Ring + tint
Selected chip
background: #E8F6FD;
box-shadow: inset 0 0 0 2px #5bbcee;
Conic badge
68%
background: conic-gradient(#5bbcee 68%, #e2e8f0 0);

Transparency

What each alpha value actually composites to. The top row is #5bbcee 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(91, 188, 238, 0.5)
rgb(91 188 238 / 50%)
#5bbcee80
hsl(200 81% 65% / 50%)
color-mix(in srgb, #5bbcee 50%, transparent)
Alpha8-digit hexFlat on white
10%#5bbcee1a#EFF8FD
20%#5bbcee33#DEF2FC
40%#5bbcee66#BDE4F8
60%#5bbcee99#9DD7F5
80%#5bbceecc#7CC9F1

Gradients from #5bbcee

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, #92D3F4, #5bbcee 45%, #0C5074);
Duotone
A short hue run reads richer than a flat fill
background: linear-gradient(120deg, #5bbcee, #4F3FEB);
Complement sweep
Loud — keep it behind large type only
background: linear-gradient(90deg, #5bbcee, #EE8D5B);
Spotlight
Hero panels and app headers
background: radial-gradient(120% 120% at 20% 0%, #AEDEF7 0%, #5bbcee 45%, #0C5074 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%, #89F3D9 0%, transparent 60%), radial-gradient(55% 55% at 85% 15%, #7780F1 0%, transparent 60%), radial-gradient(70% 70% at 50% 95%, #0C5074 0%, transparent 65%), #5bbcee;

Monochromatic scale

Palettes built from #5bbcee

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.

#5bbcee in the real world

Where a color in this family tends to land, and the interface roles it is usually asked to play.

Industries
TechnologyFinanceHealthcareEnterprise SaaS
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 9.87:1.

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.

#5bbcee, answered

What color is #5bbcee?

#5bbcee is a balanced electric blue, closest to Deep Sky Blue (ΔE2000 3.5). It sits at 200° on the hue wheel with 81% saturation and 65% lightness, which reads as cool.

What is the RGB value of #5bbcee?

rgb(91, 188, 238) — 91 red, 188 green and 238 blue out of 255, or 35.7% / 73.7% / 93.3% by channel.

What is #5bbcee in HSL and HSV?

hsl(200, 81%, 65%) and hsv(200, 62%, 93%). HSL is what CSS takes; HSV is what your design tool's picker shows, which is why the saturation numbers rarely match.

Is #5bbcee a light or a dark color?

It is a mid-tone. Relative luminance is 0.4436 and perceived brightness is 68%, so black text on it reaches 9.87:1.

Should I use black or white text on #5bbcee?

Black. It scores 9.87:1 against #5bbcee, versus 2.13:1 for white — AAA at any size.

Is #5bbcee accessible on a white background?

#5bbcee on white scores 2.13:1, which fails WCAG AA at every size. Darken it to #127CB2 to reach 4.5:1, or #0E5C84 for 7:1.

What is the complementary color of #5bbcee?

#EE8D5B sits directly opposite on the wheel. Softer options are the split-complements #EE5B72 and #EED65B, which give the same contrast with far less vibration.

What colors go well with #5bbcee?

For interface work: #F4F8FA as the surface, #C0DDED for borders, #4B809B for secondary text, #BD1E0F as an accent and #0C5074 for hover and pressed states. For a palette, the analogous pair #5BEED6 and #5B72EE stays calm, while #EE8D5B is the loudest partner.

What is #5bbcee in CMYK for printing?

cmyk(62%, 21%, 0%, 7%). 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 #5bbcee 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 #5BEEEA; nudged cooler, #59ADF0.

Which Tailwind color is closest to #5bbcee?

The sky family — its 500 step is #0ea5e9, ΔE2000 7.5 away. That is a visible difference, so define #5bbcee as a custom token rather than reaching for the built-in.

How do I use #5bbcee in Tailwind CSS?

Inline it as an arbitrary value with bg-[#5bbcee] or text-[#5bbcee], 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 #5bbcee with 50% opacity?

rgba(91, 188, 238, 0.5), or #5bbcee80 in eight-digit hex. Over white that composites to #ADDEF7; over black, #2E5E77.

Is #5bbcee a web-safe color?

No. The nearest web-safe colour is #66CCFF, ΔE2000 4.1 away. The palette only matters for legacy displays and some email clients now.

What does the color #5bbcee mean?

As a blue, it reads trusted, calm, competent. The default of institutions for a reason: blue is read as stable and safe across nearly every culture that has been surveyed. At this chroma the effect is amplified — it will dominate whatever sits beside it.

What gradient works with #5bbcee?

The safest is same-hue elevation: linear-gradient(135deg, #92D3F4, #5bbcee 45%, #0C5074). For more colour, a short hue run to #4F3FEB keeps it rich without turning muddy.

Work with #5bbcee in the Color Lab

Every tool opens with this colour already loaded.

Every value on this page is computed from #5bbcee at request time — conversions, contrast ratios and ΔE distances are calculated, never looked up.