#183B8C
Closest named color: Cobalt (#1E488F). oklch(38.1% 0.141 263.5), rgb(24, 59, 140).
Aa
White text reads best on this color (10.27:1).
About this color
#183B8C is a dark, vivid blue. In OKLCH its lightness is 38%, its chroma 0.141 and its hue 263°. Its hue sits on the cool side of the wheel. The nearest named color is Cobalt (#1E488F), ΔE 0.037 away. White text reads best on it, at 10.27:1.
| Hue family | Blues |
| Lightness | dark (38%) |
| Chroma | vivid (0.141) |
| Temperature | cool |
| Nearest name | Cobalt (#1E488F) |
| Black text | 2.04:1 |
| White text | 10.27:1 |
Values
| HEX | #183B8C |
| RGB | rgb(24, 59, 140) |
| HSL | hsl(222, 71%, 32%) |
| OKLCH | oklch(38.1% 0.141 263.5) |
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 #183B8C | 10.27:1 | AAA | Lc -97.4 | Preferred for body text |
| Black text on #183B8C | 2.04:1 | Fails | Lc 10.6 | Not readable |
| #183B8C text on white | 10.27:1 | AAA | Lc 93.3 | Preferred for body text |
| #183B8C text on black | 2.04:1 | Fails | Lc -9.2 | 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
#DFEAFF
oklch(93.5% 0.031 263.5)
-
Step 200
200
#C6DAFF
oklch(88.5% 0.056 262.8)
-
Step 300
300
#A1C1FF
oklch(81% 0.095 263.3)
-
Step 400
400
#6E9DFF
oklch(70.6% 0.153 263.6)
-
Step 500
500
#4881FF
oklch(63.2% 0.197 263.5)
-
Step 600
600
#2362FA
oklch(55.7% 0.235 263.5)
-
Step 700
700
#174FDA
oklch(49% 0.22 263.6)
-
Step 800
800
#1542B0
oklch(42.7% 0.182 263.6)
-
Step 900
900 (this color)
#183B8C
oklch(38.1% 0.141 263.5)
-
Step 950
950
#0E2351
oklch(27% 0.089 263.2)
#183B8C 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) | #00468F | 0.029 |
| Deuteranopia (no green cones) | #003B8A | 0.014 |
| Tritanopia (no blue cones) | #004F5D | 0.109 |
| Achromatopsia (no color) | #414141 | 0.141 |
Harmonies
Hue rotations in OKLCH that keep this color's lightness and chroma.
Complementary
The opposite hue (180°).
- #183B8C
#183B8C
oklch(38.1% 0.141 263.5)
- #563E00
#563E00
oklch(38% 0.078 83.8)
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 #183B8C, closest first.
Similar named colors
The eight closest entries in our named color list, with their ΔE distance.
- Cobalt #1E488F ΔE 0.037
- Twilight Blue #0A437A ΔE 0.040
- Sapphire #2138AB ΔE 0.052
- Marine Blue #01386A ΔE 0.062
- Light Navy #155084 ΔE 0.063
- Dark Slate Blue #483D8B ΔE 0.064
- Blueberry #464196 ΔE 0.065
- Dusk Blue #26538D ΔE 0.071
Use #183B8C 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.