BLUE

Cobalt

#2563EB

Conversions

HEX#2563EB

RGBrgb(37, 99, 235)

HSLhsl(221, 83%, 53%)

HSVhsv(221, 84%, 92%)

CMYKcmyk(84%, 58%, 0%, 8%)

Copy CSS

color: #2563eb;
/* rgb  */ color: rgb(37, 99, 235);
/* hsl  */ color: hsl(221, 83%, 53%);

Contrast

On whitePass · 5.17 : 1

On ink blackFail · 3.70 : 1

Shades

Tints

Pairings

About Cobalt

Cobalt is the hex color #2563EB, which translates to rgb(37, 99, 235) in RGB and hsl(221, 83%, 53%) in HSL. On the color wheel it sits at 221 degrees, with a saturation of 83 percent and a lightness of 53 percent. Its OKLCH chroma of 0.215 is high, so Cobalt is one of the more vivid blue tones here and is easy to overuse at large sizes.

How Cobalt compares

The closest standard CSS keyword is royalblue (#4169E1), a CIE76 distance of 9.9 away in CIELAB. That is a visible difference, so the keyword is not a substitute here. In the Tailwind CSS 4.3.1 palette the nearest token is blue-500 (#2B7FFF), at a distance of 13.6. Inside this library the closest neighbour is Royal Blue at 9.9. Sorted by lightness, Cobalt is number 19 of the 30 blue colors here.

Text on Cobalt

One of the five common text colors below clears WCAG AA for normal text on Cobalt, led by White at 5.17:1. The ratios are computed with the WCAG relative luminance formula, the same one the contrast checker uses, which opens with Cobalt already loaded as the background.

Contrast of common text colors on Cobalt. AA normal text needs 4.5:1, AA large text and non-text elements need 3:1, AAA normal text needs 7:1.
Text color	Ratio	AA normal	AA large	AAA normal
White #FFFFFF	5.17:1	Pass	Pass	Fail
Ink black #0F0F12	3.70:1	Fail	Pass	Fail
Mid grey #6B7280	1.07:1	Fail	Fail	Fail
Dark grey #374151	1.99:1	Fail	Fail	Fail
Light grey #E5E7EB	4.17:1	Fail	Pass	Fail

Building a palette around Cobalt

The pairings above give you three classic starting points. The complementary color sits opposite on the wheel and works well as an accent that draws the eye. The analogous colors sit right beside Cobalt for calmer, harmonious combinations. The triadic pair spaces three hues evenly for a balanced, energetic palette. Open any swatch to explore it as its own color.

Full values for Cobalt

Format	Value
HEX	#2563EB
RGB	rgb(37, 99, 235)
HSL	hsl(221, 83%, 53%)
HSV	hsv(221, 84%, 92%)
CMYK	cmyk(84%, 58%, 0%, 8%)
OKLCH	oklch(54.61% 0.2152 262.88)
CIELAB	lab(46.06 30.96 -73.83)

Use Cobalt in a tool

Nearby colors

Last updated 5 August 2026 by FusionStudios. Every value on this page is computed by the same functions the tools use. How this is calculated.