#370B9D Color

#370B9D is rgb(55, 11, 157) in RGB, hsl(258, 87%, 33%) in HSL, and about cmyk(65%, 93%, 0%, 38%) in CMYK. It has no registered color name of its own — the closest is Websafe Indigo (#330099), very hard to tell apart at ΔE 2.64. White text is the more readable choice on this background.

#370B9D

HEX#370B9D

RGBrgb(55, 11, 157)

HSLhsl(258, 87%, 33%)

HSVhsv(258, 93%, 62%)

CMYKcmyk(65%, 93%, 0%, 38%)

OKLCHoklch(35.2% 0.2 282.4)

LABlab(20.57% 47.08 -69.76)

LCHlch(20.57% 84.16 304.02)

What #370B9D Is Called

Most hex codes have no name: there are 16.7 million of them and a few thousand registered names. These are the named colors nearest to #370B9D, ordered by CIE76 distance in CIELAB. Anything under about ΔE 2 is a difference most people cannot see.

Websafe Indigo#330099ΔE 2.64 Blue Ribbon#0B10A2ΔE 7.61 Neon Blue#1B03A3ΔE 8.47 Dark Blue#00008BΔE 8.52 Blue (Pantone)#0018A8ΔE 9.19 Zaffer (Zaffre)#0014A8ΔE 9.29

Browse the full index of named colors A-Z or every purple in the library.

#370B9D Channel Values

How #370B9D breaks down in each color model. Hue is measured in degrees around the color wheel; saturation, lightness, and the CMYK inks are percentages.

Model	Channels	Notes
RGB	R 55 · G 11 · B 157	8-bit channels as sent to the display
HSL	H 258° · S 87% · L 33%	Easiest model for building lighter and darker variants
HSV	H 258° · S 93% · V 62%	Matches the picker in most design tools
CMYK	C 65% · M 93% · Y 0% · K 38%	Approximate ink mix; confirm with an ICC profile before printing
Luminance	12.37:1 vs white · 1.7:1 vs black	WCAG 2.2 relative-luminance contrast ratios

Text Contrast & Accessibility

WCAG 2.2 contrast ratios for text on a #370B9D background. AA requires 4.5:1 for normal text and 3:1 for large text; AAA requires 7:1. Contrast is one check, not a full accessibility review.

TextWhite text12.37:1AA normal AA large AAA normal

Fails AABlack text1.7:1AA normal AA large AAA normal

Need a specific ratio against another background? Open #370B9D in the contrast checker.

Colors That Go With #370B9D

Pairings derived from color-wheel relationships. The complementary color sits opposite #370B9D; analogous colors sit beside it; triadic and split-complementary sets spread evenly around the wheel. Select any swatch for its own breakdown.

Base

Complementary

Analogous

Analogous

Triadic

Triadic

Split comp.

Split comp.

Tints & Shades of #370B9D

Lighter tints and darker shades built by moving the lightness channel while holding hue and saturation, which is what you want for hover states, backgrounds, and text variants.

Tints

Shades

Want a full 50-950 ramp with semantic roles? Generate design tokens from #370B9D.

How #370B9D Looks with Color Vision Deficiency

Simulated with the Viénot, Brettel & Mollon LMS projection model. Anomalous types are rendered as partial versions of the matching dichromacy, which is an approximation rather than a per-person clinical model.

Typical#370B9D

Protanopia#18189D

Protanomaly#28149D

Deuteranopia#21219D

Deuteranomaly#2B1A9D

Tritanopia#003C3C

Tritanomaly#1E2F70

Achromatopsia#343434

Test a full palette in the color blindness simulator.

Using #370B9D in Code

Copy-ready declarations for the places this color usually ends up.

CSS custom property--color-370b9d: #370B9D;

CSS backgroundbackground-color: #370B9D;

Tailwind configcolors: { 'color-370b9d': '#370B9D' }

SwiftUIColor(red: 0.216, green: 0.043, blue: 0.616)

Android XML<color name="color_370b9d">#370B9D</color>

SVG fillfill="#370B9D"

More Purple Colors

#370B9D sits in the purple family. These are its neighbours across that family's full range, each with its own breakdown.

150024 fdf8ff 170b22 fdf4ff 1b0d35 faf5ff 1d0731 fae8ff 1e0033 f6cfff 20002e f3e8ff 300052 402060 541490 6600cc 7008e7 8806ce 9900cc a11fff b19cd9 c27aff cebeef e0b2eb

#370B9D Frequently Asked Questions

What color is #370B9D?

#370B9D is a dark purple — rgb(55, 11, 157) in RGB and hsl(258, 87%, 33%) in HSL. It carries no registered color name of its own; the closest named color is Websafe Indigo (#330099), which is very hard to tell apart at a CIE76 distance of 2.64.

What is the RGB value of #370B9D?

#370B9D is rgb(55, 11, 157) — red 55, green 11, and blue 157 on the 0-255 scale.

What is the CMYK value of #370B9D?

#370B9D converts to approximately cmyk(65%, 93%, 0%, 38%). CMYK output is a mathematical approximation for planning; confirm production print colors with your printer and ICC profile.

Should text on #370B9D be black or white?

White text is the more readable choice. #370B9D scores 12.37:1 against white and 1.7:1 against black, and WCAG 2.2 asks for at least 4.5:1 for normal body text.

Can I write #370B9D as a CSS color keyword?

No. #370B9D is not one of the CSS color keywords, so it has to be written as a hex, rgb() or hsl() value. The closest keyword is darkblue (#00008B) at a CIE76 distance of 8.52, which is clearly related but distinguishable side by side.

Open #370B9D in a Tool

Hex to RGB Hex to HSL Hex to CMYK Hex to OKLCH Hex to Pantone Build a palette Make a gradient

Keep exploring: every purple in the color library, the guide to shades of purple, or the full color library.