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blue · cool

#33acfc

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

Token name suggestion: True Harbour

RGB
51, 172, 252
HSL
204°, 97%, 59%
CMYK
80, 32, 0, 1
Luminance
0.3724

#33acfc is a balanced electric blue, 204° on the wheel and 97/100 on the cool side. Put black text on it (8.45:1). As text it scores 2.49:1 on white — use #0378C6 instead. Nearest name is Deep Sky Blue, nearest Tailwind family is sky.

hsl(204 97% 59%)rgb(51 172 252)Base step 500AAA inkCool

At a glance

Every number on this page in one read: what #33acfc is made of, how bright it looks, and which way it leans.

Hex
#33acfc
Hue
204°
blue
Saturation
97%
electric
Lightness
59%
balanced
Brightness
99%
HSV value
Perceived
62%
weighted brightness
Luminance
0.3724
WCAG relative
Temperature
Cool
97/100 cool
Color family
Blue
Tone
Electric
Best ink
Black
8.45:1
Closest name
Deep Sky Blue
ΔE2000 7.6
Chroma
49.2
LCH, 0–130ish
OKLCH L
0.716
perceptual lightness
Tailwind
sky
500 · ΔE 3.9
Web-safe
#3399FF
nearest of 216
Where it sits
Hue204° of 360°
Saturation97%
Lightness59%
Saturation × lightness field

Left edge is grey, right edge is full chroma; top is white, bottom is black. The dot is #33acfc.

Temperature
Warm ← → Cool97% 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%
Green79%
Blue19%

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

Every format

HEX#33acfc
HEX (8-digit)#33acfcff
RGBrgb(51, 172, 252)
RGBArgba(51, 172, 252, 1)
HSLhsl(204, 97%, 59%)
HSV / HSBhsv(204, 80%, 99%)
HWBhwb(204 20% 1%)
CMYKcmyk(80%, 32%, 0%, 1%)
LABlab(67.5 -5.9 -48.9)
LCHlch(67.5 49.2 263.1)
OKLCHoklch(0.716 0.155 243.2)
XYZ (D65)xyz(33.68, 37.23, 97.49)
Decimal3386620
Display P3color(display-p3 0.200 0.675 0.988)
Web-safe#3399FF

Copy-ready code

every platformclick to select
/* CSS */
color: #33acfc;
background-color: #33acfc;
/* CSS custom property */
--brand: #33acfc;
/* Tailwind (arbitrary) */
class="text-[#33acfc] bg-[#33acfc]"
/* SCSS */
$brand: #33acfc;
/* SwiftUI */
Color(red: 0.200, green: 0.675, blue: 0.988)
/* UIKit */
UIColor(red: 0.200, green: 0.675, blue: 0.988, alpha: 1)
/* Android XML */
<color name="brand">#33ACFC</color>
/* Android Compose */
Color(0xFF33ACFC)
/* Flutter */
Color(0xFF33ACFC)
/* Python / OpenCV (BGR) */
(252, 172, 51)
/* Python / PIL (RGB) */
(51, 172, 252)
/* Java AWT */
new Color(51, 172, 252)
/* .NET */
Color.FromArgb(255, 51, 172, 252)
/* OpenGL / Unity (0–1) */
(0.2000f, 0.6745f, 0.9882f, 1f)
/* LaTeX */
\definecolor{brand}{RGB}{51,172,252}
modern cssclick to select
/* mix without leaving CSS */
background: color-mix(in oklab, #33acfc 85%, white);
border-color: color-mix(in oklab, #33acfc 40%, transparent);
/* theme-aware in one line */
color: light-dark(#024C7E, #D3E3EE);
/* relative colour syntax */
--hover: hsl(from #33acfc 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: #F1F9FD;
  --brand-100: #E4F2FC;
  --brand-200: #C1E4FB;
  --brand-300: #90D2FD;
  --brand-400: #59BBFD;
  --brand-500: #33acfc;
  --brand-600: #0493F1;
  --brand-700: #037AC9;
  --brand-800: #0262A1;
  --brand-900: #074874;
  --brand-950: #042D48;
  --brand: #33acfc;
  --brand-ink: #000000;
  --brand-surface: #F4F8FA;
  --brand-border: #C0DBED;
  --brand-hover: #109EFB;
  --brand-pressed: #038BE4;
}
@media (prefers-color-scheme: dark) {
  :root {
    --brand-surface: #141E24;
    --brand-ink: #D3E3EE;
  }
}
tailwind.config.jsclick to select
theme: {
  extend: {
    colors: {
      brand: {
        50: '#F1F9FD',
        100: '#E4F2FC',
        200: '#C1E4FB',
        300: '#90D2FD',
        400: '#59BBFD',
        500: '#33acfc',
        600: '#0493F1',
        700: '#037AC9',
        800: '#0262A1',
        900: '#074874',
        950: '#042D48',
        DEFAULT: '#33acfc',
      },
    },
  },
}
scss mapclick to select
$brand: (
  '50': #F1F9FD,
  '100': #E4F2FC,
  '200': #C1E4FB,
  '300': #90D2FD,
  '400': #59BBFD,
  '500': #33acfc,
  '600': #0493F1,
  '700': #037AC9,
  '800': #0262A1,
  '900': #074874,
  '950': #042D48,
);
$brand-base: #33acfc;
$brand-ink: #000000;

@function brand($step) { @return map-get($brand, $step); }
w3c design tokens (json)click to select
{
  "color": {
    "brand": {
      "50": { "$value": "#F1F9FD", "$type": "color" },
      "100": { "$value": "#E4F2FC", "$type": "color" },
      "200": { "$value": "#C1E4FB", "$type": "color" },
      "300": { "$value": "#90D2FD", "$type": "color" },
      "400": { "$value": "#59BBFD", "$type": "color" },
      "500": { "$value": "#33acfc", "$type": "color" },
      "600": { "$value": "#0493F1", "$type": "color" },
      "700": { "$value": "#037AC9", "$type": "color" },
      "800": { "$value": "#0262A1", "$type": "color" },
      "900": { "$value": "#074874", "$type": "color" },
      "950": { "$value": "#042D48", "$type": "color" }
    },
    "brandInk": { "$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 #33acfc · 8.45:1
Use #000000AAA at every size.
Aa
12px
Aa
16px
Aa
24px
Aa
White text · 2.49:1
AA fail · AA large fail · AAA fail
Aa
Black text · 8.45:1 · recommended
AA pass · AA large pass · AAA pass
Reading the other direction: #33acfc as text scores 2.49:1 on white and 8.45:1 on black.
Best tinted ink on it, if plain black or white feels flat: #024C7E at 3.61:1.

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
#0378C6 · 4.66:1
AA on white−20% L
#0378C6
The quick fox
#025A94 · 7.26:1
AAA on white−30% L
#025A94
The quick fox
#33acfc · 8.45:1
AA on blackalready passes
#33acfc
The quick fox
#33acfc · 8.45:1
AAA on blackalready passes
#33acfc

Large text — 24px regular or 18.66px bold and above — only needs 3:1, so #0699FB 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
#33acfc on white: 2.49:1
AA ✗ fail · AA-large · AAA
Aa
#33acfc on black: 8.45:1
AA ✓ pass · AA-large · AAA
Against the neutral ladder

Contrast is symmetric, so each row covers both directions: #33acfc as text on that neutral, and that neutral as text on #33acfc.

NeutralRatioBoth directions
White2.49:1AaAa
Slate 502.38:1AaAa
Slate 1002.27:1AaAa
Slate 2002.02:1AaAa
Slate 3001.67:1AaAa
Slate 4001.03:1AaAa
Slate 5001.91:1AaAa
Slate 6003.05:1AaAa
Slate 7004.17:1AaAa
Slate 8005.88:1AaAa
Slate 9007.18:1AaAa
Black8.45:1AaAa
Colour vision deficiency
true color
protanopia · #86AEFF
deuteranopia · #6A9CFB
tritanopia · #00C0C9

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. #33acfc 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.

#F1F9FD
#E4F2FC
#C1E4FB
#90D2FD
#59BBFD
#33acfc
#0493F1
#037AC9
#0262A1
#074874
#042D48
Base = 500Lightest = 50 · #F1F9FDDarkest = 950 · #042D48Text step on white = 700
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 0.039 243.2);
  --brand-100: oklch(0.94 0.062 243.2);
  --brand-200: oklch(0.88 0.093 243.2);
  --brand-300: oklch(0.80 0.121 243.2);
  --brand-400: oklch(0.72 0.143 243.2);
  --brand-500: oklch(0.64 0.155 243.2);
  --brand-600: oklch(0.56 0.155 243.2);
  --brand-700: oklch(0.48 0.146 243.2);
  --brand-800: oklch(0.40 0.131 243.2);
  --brand-900: oklch(0.32 0.109 243.2);
  --brand-950: oklch(0.24 0.086 243.2);
}

Colors that work with #33acfc

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#C0DBED
Hairlines and dividers
Muted text#4B7B9B
Captions on the surface
Accent#FF4F30
Second voice, not a rival
Dark variant#024C7E
Hover, pressed, headers
Light variant#E6F5FF
Selected rows, tints
Dark surface#141E24
Dark-mode background
Hover#109EFB
One step down in lightness
Pressed#038BE4
Two steps down
Disabled#C5D2DA
Chroma pulled out
Focus ring#44B5FF
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 #33acfc

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 #024C7E
Safe as a 1px border on white
No — use #0699FB

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
  • Weight41/100
  • 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#FC8333
Analogous left#33FCE8
Analogous right#3347FC
Split-complement 1#FC3347
Split-complement 2#FCE833
Triadic 1#FC33AC
Triadic 2#ACFC33
Tetradic#E833FC
On the wheel
Base+30°−30°+120°+240°+180°204°

#33acfc sits at 204°. Every dot is a harmony position and links to its own page in the table alongside.

RGB percentages

Red20.0%
Green67.5%
Blue98.8%
R · 0–255
51
0x33
G · 0–255
172
0xac
B · 0–255
252
0xfc

CMYK percentages

Cyan79.8%
Magenta31.7%
Yellow0.0%
Key (black)1.2%

Total ink coverage is 113%. Most commercial presses cap around 300% — above that, sheets stop drying properly.

Color previews

#33acfc text on a black background

contrast 8.45:1

Card sample

#33acfc text on a white background

contrast 2.49:1

Card sample

#33acfc on grey

2.27:1

#33acfc on its own surface

2.33:1

#33acfc on its dark surface

6.81:1

CSS3 live lab

Text font color

The quick brown fox

color: #33acfc;
Background color
Panel with #33acfc background
background-color: #33acfc;
Text shadow — hex

Glowing headline

text-shadow: 2px 2px 8px #33acfc;
Text shadow — RGB

Soft neon halo

text-shadow: 0 0 14px rgba(51, 172, 252, 0.45);
Div box shadow
Elevated card
box-shadow: 0 12px 32px -8px rgba(51, 172, 252, 0.45);
Border & gradient
Gradient panel
border: 3px solid #33acfc;
background: linear-gradient(135deg, #33acfc, #4033FC);
Gradient text

Gradient headline

background: linear-gradient(90deg, #33acfc, #7233FC);
-webkit-background-clip: text;
color: transparent;
Focus ring
Focused control
outline: 2px solid #33acfc;
outline-offset: 3px;
Underline & caret

Marked up text

text-decoration-color: #33acfc;
caret-color: #33acfc;
Left rule
Pull quote or callout
border-left: 4px solid #33acfc;
Ring + tint
Selected chip
background: #E6F5FF;
box-shadow: inset 0 0 0 2px #33acfc;
Conic badge
68%
background: conic-gradient(#33acfc 68%, #e2e8f0 0);

Transparency

What each alpha value actually composites to. The top row is #33acfc 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(51, 172, 252, 0.5)
rgb(51 172 252 / 50%)
#33acfc80
hsl(204 97% 59% / 50%)
color-mix(in srgb, #33acfc 50%, transparent)
Alpha8-digit hexFlat on white
10%#33acfc1a#EBF7FF
20%#33acfc33#D6EEFE
40%#33acfc66#ADDEFE
60%#33acfc99#85CDFD
80%#33acfccc#5CBDFD

Gradients from #33acfc

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, #6FC4FD, #33acfc 45%, #024C7E);
Duotone
A short hue run reads richer than a flat fill
background: linear-gradient(120deg, #33acfc, #3715FC);
Complement sweep
Loud — keep it behind large type only
background: linear-gradient(90deg, #33acfc, #FC8333);
Spotlight
Hero panels and app headers
background: radial-gradient(120% 120% at 20% 0%, #8DD1FD 0%, #33acfc 45%, #024C7E 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%, #65FDE1 0%, transparent 60%), radial-gradient(55% 55% at 85% 15%, #5154FC 0%, transparent 60%), radial-gradient(70% 70% at 50% 95%, #024C7E 0%, transparent 65%), #33acfc;

Monochromatic scale

Palettes built from #33acfc

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.

#33acfc 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 8.45:1.

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.

#33acfc, answered

What color is #33acfc?

#33acfc is a balanced electric blue, closest to Deep Sky Blue (ΔE2000 7.6). It sits at 204° on the hue wheel with 97% saturation and 59% lightness, which reads as cool.

What is the RGB value of #33acfc?

rgb(51, 172, 252) — 51 red, 172 green and 252 blue out of 255, or 20% / 67.5% / 98.8% by channel.

What is #33acfc in HSL and HSV?

hsl(204, 97%, 59%) and hsv(204, 80%, 99%). HSL is what CSS takes; HSV is what your design tool's picker shows, which is why the saturation numbers rarely match.

Is #33acfc a light or a dark color?

It is a mid-tone. Relative luminance is 0.3724 and perceived brightness is 62%, so black text on it reaches 8.45:1.

Should I use black or white text on #33acfc?

Black. It scores 8.45:1 against #33acfc, versus 2.49:1 for white — AAA at any size.

Is #33acfc accessible on a white background?

#33acfc on white scores 2.49:1, which fails WCAG AA at every size. Darken it to #0378C6 to reach 4.5:1, or #025A94 for 7:1.

What is the complementary color of #33acfc?

#FC8333 sits directly opposite on the wheel. Softer options are the split-complements #FC3347 and #FCE833, which give the same contrast with far less vibration.

What colors go well with #33acfc?

For interface work: #F4F8FA as the surface, #C0DBED for borders, #4B7B9B for secondary text, #FF4F30 as an accent and #024C7E for hover and pressed states. For a palette, the analogous pair #33FCE8 and #3347FC stays calm, while #FC8333 is the loudest partner.

What is #33acfc in CMYK for printing?

cmyk(80%, 32%, 0%, 1%). 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 #33acfc warm or cool?

Cool — it scores 97 on a scale where 0 is the warmest orange and 100 the coolest azure. Nudged warmer it becomes #33F6FC; nudged cooler, #1794FE.

Which Tailwind color is closest to #33acfc?

The sky family — its 500 step is #0ea5e9, ΔE2000 3.9 away. That is a visible difference, so define #33acfc as a custom token rather than reaching for the built-in.

How do I use #33acfc in Tailwind CSS?

Inline it as an arbitrary value with bg-[#33acfc] or text-[#33acfc], 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 #33acfc with 50% opacity?

rgba(51, 172, 252, 0.5), or #33acfc80 in eight-digit hex. Over white that composites to #99D6FE; over black, #1A567E.

Is #33acfc a web-safe color?

No. The nearest web-safe colour is #3399FF, ΔE2000 6.9 away. The palette only matters for legacy displays and some email clients now.

What does the color #33acfc 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 #33acfc?

The safest is same-hue elevation: linear-gradient(135deg, #6FC4FD, #33acfc 45%, #024C7E). For more colour, a short hue run to #3715FC keeps it rich without turning muddy.

Work with #33acfc in the Color Lab

Every tool opens with this colour already loaded.

Every value on this page is computed from #33acfc at request time — conversions, contrast ratios and ΔE distances are calculated, never looked up.