Blue color · XKCD survey name
Ultramarine Blue Color Code: #1805DB
Ultramarine Blue (#1805DB) is a medium-dark, vivid blue shade: RGB 24, 5, 219, HSL 245°, 96%, 44%. White text reads comfortably on it (10.07:1 contrast).
Ultramarine Blue color values
#1805DB
rgb(24, 5, 219)
hsl(245, 96%, 44%)
245, 98%, 86%
hwb(245 2% 14%)
89%, 98%, 0%, 14%
1574363
CMYK is a standard screen-to-print conversion. Printed results depend on inks, paper and color profiles.
What is Ultramarine Blue?
“Ultramarine 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 245° places it in the blue part of the color wheel, with 96% saturation (vivid) and 44% lightness (medium-dark). It is a cool color.
Compared with the other blue colors in the Aqeeb Studio library, it is lighter than 45% of them and more saturated than 62% of them.
Its relative luminance is 0.054, 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.
Ultramarine Blue counts as a dark color: its HSL lightness is 44% and its relative luminance is 0.054. White text reads comfortably on it (10.07:1 contrast).
Text contrast on Ultramarine Blue
| Text | Preview | Ratio | AA normal | AA large | AAA normal | AAA large |
|---|---|---|---|---|---|---|
| White text | Sample text | 10.07:1 Excellent | Pass | Pass | Pass | Pass |
| Black text | Sample text | 2.08:1 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 Ultramarine 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.
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.
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.
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.
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.
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.
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 Ultramarine 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.
Similar colors
Where to use Ultramarine Blue
- Button, banner and badge backgrounds with white text (10.07:1 contrast)
- Accents that need to stand out: call-to-action buttons, charts and illustrations
- Headers and navigation bars
- Charts and dashboards
- Links, buttons and primary interface accents
- Corporate, finance and software branding
Use Ultramarine Blue in CSS
:root {
--color-ultramarine-blue: #1805DB;
}
.element {
color: var(--color-ultramarine-blue);
background-color: #1805DB;
border: 2px solid #1805DB;
}Questions about Ultramarine Blue
What is the HEX code for Ultramarine Blue?
Ultramarine Blue is #1805DB.
What is the RGB value of Ultramarine Blue?
The RGB value of Ultramarine Blue is 24, 5, 219: 24 red, 5 green and 219 blue on a 0–255 scale, written rgb(24, 5, 219) in CSS.
What is the HSL value of Ultramarine Blue?
The HSL value of Ultramarine Blue is 245°, 96%, 44% (hue, saturation, lightness), written hsl(245, 96%, 44%) in CSS.
What is the CMYK value of Ultramarine Blue?
A standard conversion gives about C 89%, M 98%, Y 0%, K 14%. Real print results depend on the inks, paper and color profile, so treat CMYK here as a reference value.
Is Ultramarine Blue a light or dark color?
Ultramarine Blue counts as a dark color: its HSL lightness is 44% and its relative luminance is 0.054. White text reads comfortably on it (10.07:1 contrast).
How does Ultramarine Blue look with white text?
White text on Ultramarine Blue has a contrast ratio of 10.07:1, rated Excellent. It meets WCAG AA for normal text.
How does Ultramarine Blue look with black text?
Black text on Ultramarine Blue has a contrast ratio of 2.08:1, rated Poor. It falls below the WCAG minimum for text.
What colors go well with Ultramarine Blue?
Banana Yellow is its complementary color, and Cerulean Blue sits beside it as an analogous color. Lighter and darker variants of the same hue also work well for monochromatic palettes.
Where can Ultramarine Blue be used?
It suits button, banner and badge backgrounds with white text (10.07:1 contrast); accents that need to stand out: call-to-action buttons, charts and illustrations; headers and navigation bars.
How do I use Ultramarine Blue in CSS?
Use color: #1805DB; for text, background-color: #1805DB; for fills, or define a custom property such as --color-ultramarine-blue: #1805DB; and reuse it with var(--color-ultramarine-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.