#1B377D
Closest named color: Twilight Blue (#0A437A). oklch(36% 0.124 264.5), rgb(27, 55, 125).
Aa
White text reads best on this color (11.11:1).
About this color
#1B377D is a dark, moderately saturated blue. In OKLCH its lightness is 36%, its chroma 0.124 and its hue 264°. Its hue sits on the cool side of the wheel. The nearest named color is Twilight Blue (#0A437A), ΔE 0.035 away. White text reads best on it, at 11.11:1.
| Hue family | Blues |
| Lightness | dark (36%) |
| Chroma | moderately saturated (0.124) |
| Temperature | cool |
| Nearest name | Twilight Blue (#0A437A) |
| Black text | 1.88:1 |
| White text | 11.11:1 |
Values
| HEX | #1B377D |
| RGB | rgb(27, 55, 125) |
| HSL | hsl(223, 64%, 30%) |
| OKLCH | oklch(36% 0.124 264.5) |
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 #1B377D | 11.11:1 | AAA | Lc -99.1 | Preferred for body text |
| Black text on #1B377D | 1.88:1 | Fails | Lc 8.6 | Not readable |
| #1B377D text on white | 11.11:1 | AAA | Lc 95.3 | Preferred for body text |
| #1B377D text on black | 1.88:1 | Fails | Lc -7.4 | 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
#F1F6FE
oklch(97.2% 0.012 259.8)
-
Step 100
100
#E1EAFD
oklch(93.6% 0.028 265.4)
-
Step 200
200
#C8D9FC
oklch(88.4% 0.052 264.8)
-
Step 300
300
#A3C0FD
oklch(80.9% 0.092 264.7)
-
Step 400
400
#729DFD
oklch(70.7% 0.149 264.7)
-
Step 500
500
#4E81FB
oklch(63.2% 0.19 264.5)
-
Step 600
600
#3366EA
oklch(55.5% 0.207 264.5)
-
Step 700
700
#2754CB
oklch(49.1% 0.191 264.5)
-
Step 800
800
#2146A4
oklch(42.8% 0.158 264.4)
-
Step 900
900 (this color)
#1B377D
oklch(36% 0.124 264.5)
-
Step 950
950
#13244C
oklch(27.1% 0.077 264.5)
#1B377D 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) | #00407F | 0.027 |
| Deuteranopia (no green cones) | #00377C | 0.018 |
| Tritanopia (no blue cones) | #004854 | 0.098 |
| Achromatopsia (no color) | #3C3C3C | 0.124 |
Harmonies
Hue rotations in OKLCH that keep this color's lightness and chroma.
Complementary
The opposite hue (180°).
- #1B377D
#1B377D
oklch(36% 0.124 264.5)
- #4F3900
#4F3900
oklch(36% 0.074 84.3)
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 #1B377D, closest first.
Similar named colors
The eight closest entries in our named color list, with their ΔE distance.
- Twilight Blue #0A437A ΔE 0.035
- Marine Blue #01386A ΔE 0.039
- Cobalt #1E488F ΔE 0.055
- Marine #042E60 ΔE 0.061
- Prussian Blue #1D3557 ΔE 0.066
- Dark Slate Blue #483D8B ΔE 0.071
- Light Navy #155084 ΔE 0.072
- Sapphire #2138AB ΔE 0.077
Use #1B377D 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.