#1B4381
Closest named color: Twilight Blue (#0A437A). oklch(39.1% 0.114 259.1), rgb(27, 67, 129).
Aa
White text reads best on this color (9.69:1).
About this color
#1B4381 is a dark, moderately saturated blue. In OKLCH its lightness is 39%, its chroma 0.114 and its hue 259°. Its hue sits on the cool side of the wheel. The nearest named color is Twilight Blue (#0A437A), ΔE 0.017 away. White text reads best on it, at 9.69:1.
| Hue family | Blues |
| Lightness | dark (39%) |
| Chroma | moderately saturated (0.114) |
| Temperature | cool |
| Nearest name | Twilight Blue (#0A437A) |
| Black text | 2.16:1 |
| White text | 9.69:1 |
Values
| HEX | #1B4381 |
| RGB | rgb(27, 67, 129) |
| HSL | hsl(216, 65%, 31%) |
| OKLCH | oklch(39.1% 0.114 259.1) |
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 #1B4381 | 9.69:1 | AAA | Lc -96.3 | Preferred for body text |
| Black text on #1B4381 | 2.16:1 | Fails | Lc 11.9 | Not readable |
| #1B4381 text on white | 9.69:1 | AAA | Lc 92.1 | Preferred for body text |
| #1B4381 text on black | 2.16:1 | Fails | Lc -10.3 | 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
#F1F6FD
oklch(97.1% 0.011 256.7)
-
Step 100
100
#E0EBFB
oklch(93.7% 0.025 257.6)
-
Step 200
200
#C7DBF9
oklch(88.6% 0.047 258.4)
-
Step 300
300
#A0C2F8
oklch(80.9% 0.085 259.5)
-
Step 400
400
#6BA1F5
oklch(70.8% 0.136 258.9)
-
Step 500
500
#4286F1
oklch(63.1% 0.175 259.2)
-
Step 600
600
#206DE0
oklch(55.6% 0.19 259.1)
-
Step 700
700
#125AC2
oklch(49% 0.177 259.1)
-
Step 800
800
#134A9D
oklch(42.6% 0.147 259.3)
-
Step 900
900 (this color)
#1B4381
oklch(39.1% 0.114 259.1)
-
Step 950
950
#0F2549
oklch(26.9% 0.073 259.8)
#1B4381 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) | #224983 | 0.020 |
| Deuteranopia (no green cones) | #084080 | 0.016 |
| Tritanopia (no blue cones) | #00525B | 0.090 |
| Achromatopsia (no color) | #444444 | 0.114 |
Harmonies
Hue rotations in OKLCH that keep this color's lightness and chroma.
Complementary
The opposite hue (180°).
- #1B4381
#1B4381
oklch(39.1% 0.114 259.1)
- #5C3F00
#5C3F00
oklch(39% 0.081 79.2)
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 #1B4381, closest first.
Similar named colors
The eight closest entries in our named color list, with their ΔE distance.
- Twilight Blue #0A437A ΔE 0.017
- Cobalt #1E488F ΔE 0.027
- Light Navy #155084 ΔE 0.038
- Deep Sea Blue #015482 ΔE 0.050
- Dusk Blue #26538D ΔE 0.051
- Marine Blue #01386A ΔE 0.054
- Dark Slate Blue #483D8B ΔE 0.061
- Blueberry #464196 ΔE 0.065
Use #1B4381 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.