#1B3666
Closest named color: Marine Blue (#01386A). oklch(34% 0.091 260.9), rgb(27, 54, 102).
Aa
White text reads best on this color (11.89:1).
About this color
#1B3666 is a dark, moderately saturated blue. In OKLCH its lightness is 34%, its chroma 0.091 and its hue 261°. Its hue sits on the cool side of the wheel. The nearest named color is Marine Blue (#01386A), ΔE 0.018 away. White text reads best on it, at 11.89:1.
| Hue family | Blues |
| Lightness | dark (34%) |
| Chroma | moderately saturated (0.091) |
| Temperature | cool |
| Nearest name | Marine Blue (#01386A) |
| Black text | 1.76:1 |
| White text | 11.89:1 |
Values
| HEX | #1B3666 |
| RGB | rgb(27, 54, 102) |
| HSL | hsl(218, 58%, 25%) |
| OKLCH | oklch(34% 0.091 260.9) |
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 #1B3666 | 11.89:1 | AAA | Lc -100.6 | Preferred for body text |
| Black text on #1B3666 | 1.76:1 | Fails | Lc 0.0 | Not readable |
| #1B3666 text on white | 11.89:1 | AAA | Lc 97.0 | Preferred for body text |
| #1B3666 text on black | 1.76:1 | Fails | Lc 0.0 | 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
#F2F6FC
oklch(97.2% 0.009 258.3)
-
Step 100
100
#E3EAF7
oklch(93.6% 0.019 263)
-
Step 200
200
#CBDAF3
oklch(88.5% 0.038 260.7)
-
Step 300
300
#A8C2ED
oklch(80.9% 0.067 260.4)
-
Step 400
400
#7AA1E4
oklch(70.7% 0.108 260.9)
-
Step 500
500
#5788DD
oklch(63.2% 0.139 260.7)
-
Step 600
600
#3D70CA
oklch(55.6% 0.15 260.8)
-
Step 700
700
#2F5DAF
oklch(49.1% 0.14 260.9)
-
Step 800
800
#284C8E
oklch(42.7% 0.117 261.4)
-
Step 900
900 (this color)
#1B3666
oklch(34% 0.091 260.9)
-
Step 950
950
#162642
oklch(27% 0.057 260.9)
#1B3666 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) | #1E3B68 | 0.016 |
| Deuteranopia (no green cones) | #113465 | 0.012 |
| Tritanopia (no blue cones) | #004149 | 0.072 |
| Achromatopsia (no color) | #373737 | 0.091 |
Harmonies
Hue rotations in OKLCH that keep this color's lightness and chroma.
Complementary
The opposite hue (180°).
- #1B3666
#1B3666
oklch(34% 0.091 260.9)
- #4A3300
#4A3300
oklch(33.9% 0.07 80.9)
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 #1B3666, closest first.
Similar named colors
The eight closest entries in our named color list, with their ΔE distance.
- Marine Blue #01386A ΔE 0.018
- Prussian Blue #1D3557 ΔE 0.026
- Marine #042E60 ΔE 0.035
- Twilight Blue #0A437A ΔE 0.047
- Dark Blue Grey #1F3B4D ΔE 0.051
- Midnight Green #073B4C ΔE 0.055
- Dark Grey Blue #29465B ΔE 0.062
- Gunmetal #293241 ΔE 0.066
Use #1B3666 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.