#178DFD

sRGB · 23 / 141 / 253

#178DFD belongs to the azure family. Its hex code tells a screen to mix 23 red, 141 green and 253 blue on a scale of 0 to 255. On the HSL wheel, hue is a position around a circle: 209.2° lands in the azure region. Its 98.3% saturation makes it strong in color at this lightness. HSL lightness is 54.1% on a scale from black (0%) to white (100%). Of black and white lettering, black has the clearer light-to-dark separation on this background (6.26:1), which helps the shapes of letters stand out.

Color conversions

sRGB (8-bit): 23, 141, 253
HSL: 209.22°, 98.29%, 54.12%
HSV / HSB: 209.22°, 90.91%, 99.22%
CMYK (approx.): 90.91%, 44.27%, 0.00%, 0.78%
CIE XYZ (D65, Y = 100 for white): 27.606, 26.322, 96.557
CIELAB (D65, 2° observer): 58.342, 10.687, -63.961
WCAG relative luminance: 0.26324
24-bit decimal: 1543677

CMYK uses a profile-free approximation. Printed output depends on the press, ink and paper. Lab uses a D65 white point.

Text contrast

Contrast tells you how clearly lettering separates from #178DFD in light and dark. The ratio compares relative luminance, a measure of light weighted for human vision. Identical colors give 1:1 and black against white gives 21:1. A ratio of 2.99:1 falls just below the 3:1 AA minimum for large text. Body text needs at least 4.5:1 because its finer strokes are harder to distinguish.

Black text · 6.26:1

Normal text: AA
Large text: AAA

White text · 3.35:1

Normal text: Fail
Large text: AA

AA and AAA are WCAG accessibility levels. AAA sets a higher bar: 7:1 for normal text and 4.5:1 for large text. Large text begins at 18 pt regular or 14 pt bold. Ratings use the unrounded ratio. WCAG text contrast guidance

Palettes & scales

Harmonies rotate the hue. Scales mix the starting color with white, black or middle gray in 20% steps in encoded sRGB.

Complementary

#FD8717 sits half a turn (180°) from #178DFD on the HSL wheel. Keeping saturation and lightness steady while crossing to the opposite hue gives you a contrasting accent. Check text contrast separately before using the pair for lettering.

#178DFD #FD8717

Analogous

#17FDFA and #171AFD sit 30° to either side of #178DFD. The three hues are neighbors on the wheel, so you can change the color of a border or highlight while keeping it close to the original.

#17FDFA #178DFD #171AFD

Triadic

#178DFD, #FD178D and #8DFD17 are spaced 120° apart, forming a triangle on the wheel. Try one for the main color and the other two for accents.

#178DFD #FD178D #8DFD17

Split complementary

Start at #178DFD and look across the wheel. #FD171A and #FDFA17 sit 30° to either side of its exact opposite, giving you two different accent choices.

#178DFD #FD171A #FDFA17

Square

Starting with #178DFD, each quarter turn (90°) takes you to the next hue: #FA17FD, #FD8717, then #1AFD17. Across the square, #178DFD pairs with #FD8717, and #FA17FD with #1AFD17.

#178DFD #FA17FD #FD8717 #1AFD17

Tetradic

#178DFD and #FD8717 are opposites, as are #8717FD and #8DFD17. Together they form a rectangle on the wheel, with alternating gaps of 60° and 120°.

#178DFD #8717FD #FD8717 #8DFD17

Tints

Mixing #178DFD with white in 20% steps produces this scale. The first mixture, #45A4FD, keeps 80% of the original. By #D1E8FF, the mixture is 80% white.

#178DFD #45A4FD #74BBFE #A2D1FE #D1E8FF #FFFFFF

Shades

Mixing #178DFD with black in 20% steps produces this scale. The first mixture, #1271CA, keeps 80% of the original. By #051C33, the mixture is 80% black.

#178DFD #1271CA #0E5598 #093865 #051C33 #000000

Tones

Mixing #178DFD with middle gray in 20% steps produces this scale. The first mixture, #2C8AE4, keeps 80% of the original. By #6B8399, the mixture is 80% middle gray.

#178DFD #2C8AE4 #4188CB #5685B2 #6B8399 #808080

Copy color codes

Hex, RGB and HSL are three ways to write this screen color. Paste any of them into a CSS color property.

Hex

#178DFD

RGB

rgb(23 141 253)

HSL

hsl(209.217 98.291% 54.118%)

CSS example

.color-sample {
  background-color: #178DFD;
  color: #000000;
}

Channel breakdown

RGB

#178DFD uses 23 red, 141 green and 253 blue. Each bar shows how much of that channel’s 0–255 range the screen uses.

Red 9.0%

Green 55.3%

Blue 99.2%

CMYK

A simple CMYK estimate for #178DFD is 90.9% cyan, 44.3% magenta, 0.0% yellow and 0.8% black. These are ink amounts; a printer profile is needed to predict the result on paper.

Cyan 90.9%

Magenta 44.3%

Yellow 0.0%

Black 0.8%

Nearby colors

The nearest shorthand match is #1188FF. Its matching digit pairs let you write it as #18F in CSS. For a modern design, keep #178DFD when you want an exact match. Use its web-safe neighbor, #0099FF, when matching a legacy palette of 216 colors.

Nearest shorthand · #1188FF Nearest web-safe · #0099FF

Gradient to complement

#178DFD #3D8CD7 #648BB0 #8A8A8A #B08964 #D7883D #FD8717

Color vision previews

Compare how #178DFD appears in each simulation. When two chart lines or status indicators become hard to tell apart, a label, shape or line pattern gives readers another way to distinguish them. Individual perception varies.

Protanopia

A red–green color vision deficiency. Without a distinct response from long-wavelength cones, some reds and greens can look alike, and reds can appear darker.

#5097FF

Deuteranopia

A red–green color vision deficiency. Without a distinct response from medium-wavelength cones, some greens can be difficult to distinguish from reds or browns.

#1783FB

Tritanopia

A blue–yellow color vision deficiency. Without a distinct response from short-wavelength cones, blue can resemble green, and yellow can resemble pink.

#00A8B9

Protanomaly (50%)

An altered long-wavelength cone response can make reds appear dimmer and harder to distinguish from greens. This swatch shows the model’s halfway setting.

#3F92FF

Deuteranomaly (50%)

An altered medium-wavelength cone response can reduce the visible difference between reds and greens. This swatch shows the model’s halfway setting.

#1F88FC

Tritanomaly (50%)

An altered short-wavelength cone response can make blue harder to distinguish from green. This swatch shows the model’s halfway setting.

#0095E7

Grayscale (luminance)

This design check removes hue and preserves relative luminance so you can compare light and dark areas.

#8C8C8C

Partial grayscale (50% blend)

This design check mixes the original color halfway toward its grayscale equivalent in linear light. Use it to see how a design holds up as color fades.

#678DCF

Technical reference

CAM16 and CIECAM02 below assume D65 white, an average surround, background Y of 20 against white at 100, and adapting luminance of 4.07 cd/m².

Linear sRGB

These channels scale with emitted light. Use them for lighting calculations and physically meaningful blends.

R 0.00857 G 0.26636 B 0.98225

Display P3

P3 displays can reproduce a wider range of reds and greens. These coordinates reproduce this same sRGB swatch on a color-managed P3 display.

R 0.25848 G 0.54473 B 0.96110

Linear Display P3

These P3 channels are proportional to light, before display encoding.

R 0.05434 G 0.25780 B 0.91379

CIE xyY

The x and y coordinates locate chromaticity on a diagram. Y gives relative luminance on a scale where white is 100.

x 0.183 y 0.175 Y 26.322

CMY

Ideal cyan, magenta and yellow are the complements of the encoded red, green and blue channels.

C % 90.980 M % 44.706 Y % 0.784

Binary RGB

Each eight-bit group represents one channel. Together they store the 24-bit hex color.

00010111 10001101 11111101