Indigo Blue Color Code: #3A18B1, RGB & HSL

Indigo Blue color values

HEX #3A18B1

RGB rgb(58, 24, 177)

HSL hsl(253, 76%, 39%)

HSV 253, 86%, 69%

HWB hwb(253 9% 31%)

CMYK 67%, 86%, 0%, 31%

Decimal 3807409

39%HSL lightness (medium-dark)

76%HSL saturation (vivid)

253°Hue angle (blue)

0.047Relative luminance

CMYK is a standard screen-to-print conversion. Printed results depend on inks, paper and color profiles.

What is Indigo Blue?

“Indigo Blue” is a crowd-sourced name from the XKCD Color Survey, in which participants typed names for colors they were shown. It is a popular everyday label rather than an official standard.

Its hue angle of 253° places it in the blue part of the color wheel, with 76% saturation (vivid) and 39% lightness (medium-dark). It is a cool color.

Compared with the other blue colors in the Aqeeb Studio library, it is lighter than 28% of them and more saturated than 39% of them.

Its relative luminance is 0.047, which makes it a dark color. That is below the 0.179 crossover point at which black and white text have equal contrast, so white text has the advantage.

Indigo Blue counts as a dark color: its HSL lightness is 39% and its relative luminance is 0.047. White text reads comfortably on it (10.79:1 contrast).

Text contrast on Indigo Blue

WCAG contrast of white and black text on Indigo Blue
Text	Preview	Ratio	AA normal	AA large	AAA normal	AAA large
White text	Sample text	10.79:1 Excellent	Pass	Pass	Pass	Pass
Black text	Sample text	1.94:1 Poor	Fail	Fail	Fail	Fail

Ratios use the WCAG 2 formula and are truncated, never rounded up. Test any pair with the contrast checker.

Colors that go with Indigo Blue

Complementary color

Complementary colors sit directly opposite each other on the color wheel (180° apart). They give the strongest hue contrast, which suits calls to action and accents.

≈ Pea Green#8FB118

Analogous colors

Analogous colors are neighbors on the wheel, 30° either side of the base hue. They blend smoothly and are easy to combine in backgrounds, gradients and illustrations.

≈ Sapphire#1842B1 ≈ Dark Orchid#8718B1

Triadic colors

A triadic scheme uses three hues spaced 120° apart. It is lively yet balanced, and works best when one color leads and the other two act as accents.

≈ Rusty Red#B13A18 ≈ Kelly Green#18B13A

Split-complementary colors

Split-complementary keeps the base color and uses the two colors on either side of its complement (150° and 210°). The contrast is strong but gentler than a direct complement.

≈ Mustard Brown#B18718 ≈ Frog Green#42B118

Tetradic colors

A tetradic (rectangle) scheme combines two complementary pairs at 0°, 60°, 180° and 240°. It offers variety but needs one dominant color to stay balanced.

≈ Medium Violet Red#B1188F ≈ Pea Green#8FB118 ≈ Kelly Green#18B13A

Monochromatic variants

Monochromatic variants keep the same hue and saturation and only change lightness, which makes them dependable for UI scales and subtle layered designs.

#110733#110733

#250F72#250F72

#3A18B1#3A18B1

#562EE3#562EE3

#896DEB#896DEB

A “≈” before a name means the exact harmony color has no named match, so the link goes to the closest named color.

Tints and shades of Indigo Blue

Lighter tints (mixed with white)

Darker shades (mixed with black)

Select any swatch to copy its HEX code. Build longer scales with the tints and shades tool.

Cobalt Blue#030AA7 Ultramarine#2000B1 Blue Purple#5729CE Dark Blue#00008B Violet Blue#510AC9 Royal#0C1793 Navy#000080 True Blue#010FCC

Where to use Indigo Blue

Button, banner and badge backgrounds with white text (10.79:1 contrast)
Accents that need to stand out: call-to-action buttons, charts and illustrations
Corporate, finance and software branding
Headers and navigation bars
Charts and dashboards
Links, buttons and primary interface accents

Use Indigo Blue in CSS

:root {
  --color-indigo-blue: #3A18B1;
}

.element {
  color: var(--color-indigo-blue);
  background-color: #3A18B1;
  border: 2px solid #3A18B1;
}

Questions about Indigo Blue

What is the HEX code for Indigo Blue?

Indigo Blue is #3A18B1.

What is the RGB value of Indigo Blue?

The RGB value of Indigo Blue is 58, 24, 177: 58 red, 24 green and 177 blue on a 0–255 scale, written rgb(58, 24, 177) in CSS.

What is the HSL value of Indigo Blue?

The HSL value of Indigo Blue is 253°, 76%, 39% (hue, saturation, lightness), written hsl(253, 76%, 39%) in CSS.

What is the CMYK value of Indigo Blue?

A standard conversion gives about C 67%, M 86%, Y 0%, K 31%. Real print results depend on the inks, paper and color profile, so treat CMYK here as a reference value.

Is Indigo Blue a light or dark color?

Indigo Blue counts as a dark color: its HSL lightness is 39% and its relative luminance is 0.047. White text reads comfortably on it (10.79:1 contrast).

How does Indigo Blue look with white text?

White text on Indigo Blue has a contrast ratio of 10.79:1, rated Excellent. It meets WCAG AA for normal text.

How does Indigo Blue look with black text?

Black text on Indigo Blue has a contrast ratio of 1.94:1, rated Poor. It falls below the WCAG minimum for text.

What colors go well with Indigo Blue?

Pea Green is its complementary color, and Sapphire sits beside it as an analogous color. Lighter and darker variants of the same hue also work well for monochromatic palettes.

Where can Indigo Blue be used?

It suits button, banner and badge backgrounds with white text (10.79:1 contrast); accents that need to stand out: call-to-action buttons, charts and illustrations; corporate, finance and software branding.

How do I use Indigo Blue in CSS?

Use color: #3A18B1; for text, background-color: #3A18B1; for fills, or define a custom property such as --color-indigo-blue: #3A18B1; and reuse it with var(--color-indigo-blue).

About this color page

Crowd-sourced name from the XKCD Color Survey (CC0). Values are calculated from the HEX code; color names are labels, not trademarks or standards unless stated. Screens render colors differently, so always check important colors on your own device. See the disclaimer.

Indigo Blue Color Code: #3A18B1