#18378E
Closest named color: Cobalt (#1E488F). oklch(37.4% 0.149 264.9), rgb(24, 55, 142).
Aa
White text reads best on this color (10.62:1).
About this color
#18378E is a dark, vivid blue. In OKLCH its lightness is 37%, its chroma 0.149 and its hue 265°. Its hue sits on the cool side of the wheel. The nearest named color is Cobalt (#1E488F), ΔE 0.047 away. White text reads best on it, at 10.62:1.
| Hue family | Blues |
| Lightness | dark (37%) |
| Chroma | vivid (0.149) |
| Temperature | cool |
| Nearest name | Cobalt (#1E488F) |
| Black text | 1.97:1 |
| White text | 10.62:1 |
Values
| HEX | #18378E |
| RGB | rgb(24, 55, 142) |
| HSL | hsl(224, 71%, 33%) |
| OKLCH | oklch(37.4% 0.149 264.9) |
Contrast
WCAG 2 contrast ratios are the conformance target: AA needs 4.5:1 for body text and 3:1 for large text, AAA needs 7:1. APCA Lc values are supplementary guidance from the WCAG 3 drafts.
| Pair | WCAG 2 | Result | APCA | APCA guidance |
|---|---|---|---|---|
| White text on #18378E | 10.62:1 | AAA | Lc -98.1 | Preferred for body text |
| Black text on #18378E | 1.97:1 | Fails | Lc 9.9 | Not readable |
| #18378E text on white | 10.62:1 | AAA | Lc 94.0 | Preferred for body text |
| #18378E text on black | 1.97:1 | Fails | Lc -8.5 | Not readable |
Tints and shades
A 50–950 scale built in OKLCH: the hue is held, lightness follows a Tailwind v4-like curve, and every step is kept inside the sRGB gamut. This color sits at step 900.
-
Step 50
50
#F1F6FF
oklch(97.2% 0.013 262.4)
-
Step 100
100
#E0EAFF
oklch(93.6% 0.03 265.3)
-
Step 200
200
#C7D9FF
oklch(88.4% 0.056 265.2)
-
Step 300
300
#A2C0FF
oklch(80.9% 0.096 264.7)
-
Step 400
400
#719CFF
oklch(70.6% 0.153 265)
-
Step 500
500
#4D80FF
oklch(63.2% 0.197 264.8)
-
Step 600
600
#295EFF
oklch(55.5% 0.245 264.9)
-
Step 700
700
#1D4BE0
oklch(49.1% 0.23 264.9)
-
Step 800
800
#193FB5
oklch(42.7% 0.191 265)
-
Step 900
900 (this color)
#18378E
oklch(37.4% 0.149 264.9)
-
Step 950
950
#0F2254
oklch(27.1% 0.095 264.9)
#18378E with color blindness
Simulated with the Machado et al. (2009) model. ΔE is how far the color moves: below about 0.02 you would not notice a change.
| Vision | Seen as | Shift (ΔE) |
|---|---|---|
| Protanopia (no red cones) | #004491 | 0.034 |
| Deuteranopia (no green cones) | #00398C | 0.014 |
| Tritanopia (no blue cones) | #004D5D | 0.114 |
| Achromatopsia (no color) | #3E3E3E | 0.149 |
Harmonies
Hue rotations in OKLCH that keep this color's lightness and chroma.
Complementary
The opposite hue (180°).
- #18378E
#18378E
oklch(37.4% 0.149 264.9)
- #533D00
#533D00
oklch(37.4% 0.077 85.6)
Analogous
Neighbouring hues, 30° either side.
Split complementary
The two hues beside the complement (150° and 210°).
Triadic
Three hues spaced 120° apart.
Palettes with this color
Curated palettes that contain a color within ΔE 0.04 (OKLab) of #18378E, closest first.
Similar named colors
The eight closest entries in our named color list, with their ΔE distance.
- Cobalt #1E488F ΔE 0.047
- Twilight Blue #0A437A ΔE 0.049
- Sapphire #2138AB ΔE 0.049
- Marine Blue #01386A ΔE 0.064
- Royal #0C1793 ΔE 0.067
- Dark Slate Blue #483D8B ΔE 0.069
- Blueberry #464196 ΔE 0.070
- Light Navy #155084 ΔE 0.074
Use #18378E in your product
Turn it into light and dark UI roles checked for contrast, then export to Tailwind v4, shadcn/ui, CSS or design tokens.