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#288ccc

a balanced, vivid blue · cool · closest name: Steel Blue

RGB
40, 140, 204
HSL
203°, 67%, 48%
CMYK
80, 31, 0, 20
Luminance
0.2357

At a glance

Every number on this page in one read: what #288ccc is made of, how bright it looks, and which way it leans.

Hex
#288ccc
Hue
203°
blue
Saturation
67%
vivid
Lightness
48%
balanced
Brightness
80%
HSV value
Perceived
51%
weighted brightness
Luminance
0.2357
WCAG relative
Temperature
Cool
97/100 cool
Color family
Blue
Tone
Vivid
Best ink
Black
5.71:1
Closest name
Steel Blue
ΔE2000 4.7
Where it sits
Hue203° of 360°
Saturation67%
Lightness48%
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.

Every format

HEX#288ccc
RGBrgb(40, 140, 204)
HSLhsl(203, 67%, 48%)
CMYKcmyk(80%, 31%, 0%, 20%)
LABlab(55.6 -5.8 -40.9)
LCHlch(55.6 41.4 261.9)
OKLCHoklch(0.614 0.131 242.3)
Decimal2657484
Display P3color(display-p3 0.157 0.549 0.800)

Copy-ready code

/* CSS */
color: #288ccc;
background-color: #288ccc;
/* Tailwind (arbitrary) */
class="text-[#288ccc] bg-[#288ccc]"
/* SCSS */
$brand: #288ccc;
/* SwiftUI */
Color(red: 0.157, green: 0.549, blue: 0.800)
/* Android */
Color.parseColor("#288ccc")
/* Flutter */
Color(0xFF288CCC)
/* Python / OpenCV (BGR) */
(204, 140, 40)

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 #288ccc · 5.71:1
Use #000000AA at every size, AAA for large text only.
Aa
White text · 3.68:1
AA fail · AA large pass · AAA fail
Aa
Black text · 5.71:1 · recommended
AA pass · AA large pass · AAA fail
Reading the other direction: #288ccc as text scores 3.68:1 on white and 5.71:1 on black.

Accessibility — WCAG contrast

Aa
#288ccc on white: 3.68:1
AA ✗ fail · AA-large · AAA
Aa
#288ccc on black: 5.71:1
AA ✓ pass · AA-large · AAA
true color
protanopia · #6E8ECF
deuteranopia · #577FCB
tritanopia · #009CA3

Color scale — 50 to 950

A Tailwind-shaped ramp built around this exact hex. #288ccc 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.

#F3F8FB
#E8F1F8
#CAE2F1
#A1CFED
#72B7E3
#439FDA
#288ccc
#2175AB
#1B5E88
#174663
#0F2B3E
Base = 600Lightest = 50 · #F3F8FBDarkest = 950 · #0F2B3E
:root {
  --brand-50: #F3F8FB;
  --brand-100: #E8F1F8;
  --brand-200: #CAE2F1;
  --brand-300: #A1CFED;
  --brand-400: #72B7E3;
  --brand-500: #439FDA;
  --brand-600: #288ccc;
  --brand-700: #2175AB;
  --brand-800: #1B5E88;
  --brand-900: #174663;
  --brand-950: #0F2B3E;
  --brand: #288ccc;
  --brand-ink: #000000;
}

Colors that work with #288ccc

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#4B7C9B
Captions on the surface
Accent#D13B23
Second voice, not a rival
Dark variant#15496B
Hover, pressed, headers
Light variant#EAF4FB
Selected rows, tints
Dark surface#141E24
Dark-mode background
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

How to use #288ccc

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

Works well for
  • Headings from 24px up on white
  • Text and icons on dark surfaces
  • Primary buttons and calls to action
  • Focus rings, active and selected states
  • Brand accents, badges and data highlights
Use with care
  • Small text on white — under 4.5:1
  • Full-page backgrounds — tiring over long sessions
  • Pairing with a same-lightness hue — edges vibrate

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#CC6828
Analogous left#28CCBA
Analogous right#283ACC
Split-complement 1#CC283A
Split-complement 2#CCBA28
Triadic 1#CC288C
Triadic 2#8CCC28
Tetradic#BA28CC

RGB percentages

Red15.7%
Green54.9%
Blue80.0%

CMYK percentages

Cyan80.4%
Magenta31.4%
Yellow0.0%
Key (black)20.0%

Color previews

#288ccc text on a black background

contrast 5.71:1

Card sample

#288ccc text on a white background

contrast 3.68:1

Card sample

CSS3 live lab

Text font color

The quick brown fox

color: #288ccc;
Background color
Panel with #288ccc background
background-color: #288ccc;
Text shadow — hex

Glowing headline

text-shadow: 2px 2px 8px #288ccc;
Text shadow — RGB

Soft neon halo

text-shadow: 0 0 14px rgba(40, 140, 204, 0.45);
Div box shadow
Elevated card
box-shadow: 0 12px 32px -8px rgba(40, 140, 204, 0.45);
Border & gradient
Gradient panel
border: 3px solid #288ccc;
background: linear-gradient(135deg, #288ccc, #3128CC);

Monochromatic scale

Palettes built from #288ccc

Shades — darker

Tints — lighter

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.

#288ccc 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

Converts to four-color process without much drama. Proof it anyway.

#288ccc, answered

What color is #288ccc?

#288ccc is a balanced vivid blue, closest to Steel Blue (ΔE2000 4.7). It sits at 203° on the hue wheel with 67% saturation and 48% lightness, which reads as cool.

What is the RGB value of #288ccc?

rgb(40, 140, 204) — 40 red, 140 green and 204 blue out of 255, or 15.7% / 54.9% / 80% by channel.

Is #288ccc a light or a dark color?

It is a mid-tone. Relative luminance is 0.2357 and perceived brightness is 51%, so black text on it reaches 5.71:1.

Should I use black or white text on #288ccc?

Black. It scores 5.71:1 against #288ccc, versus 3.68:1 for white — AA at any size.

What is the complementary color of #288ccc?

#CC6828 sits directly opposite on the wheel. Softer options are the split-complements #CC283A and #CCBA28, which give the same contrast with far less vibration.

What colors go well with #288ccc?

For interface work: #F4F8FA as the surface, #C0DBED for borders, #4B7C9B for secondary text, #D13B23 as an accent and #15496B for hover and pressed states. For a palette, the analogous pair #28CCBA and #283ACC stays calm, while #CC6828 is the loudest partner.

What is #288ccc in CMYK for printing?

cmyk(80%, 31%, 0%, 20%). This is a screen-to-ink approximation — ask your printer for a proof before committing to a run.

Is #288ccc 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 #28C8CC; nudged cooler, #2272B9.

Work with #288ccc in the Color Lab