#1B3777
Closest named color: Marine Blue (#01386A). oklch(35.5% 0.115 263.8), rgb(27, 55, 119).
Aa
White text reads best on this color (11.29:1).
About this color
#1B3777 is a dark, moderately saturated blue. In OKLCH its lightness is 36%, its chroma 0.115 and its hue 264°. Its hue sits on the cool side of the wheel. The nearest named color is Marine Blue (#01386A), ΔE 0.030 away. White text reads best on it, at 11.29:1.
| Hue family | Blues |
| Lightness | dark (36%) |
| Chroma | moderately saturated (0.115) |
| Temperature | cool |
| Nearest name | Marine Blue (#01386A) |
| Black text | 1.85:1 |
| White text | 11.29:1 |
Values
| HEX | #1B3777 |
| RGB | rgb(27, 55, 119) |
| HSL | hsl(222, 63%, 29%) |
| OKLCH | oklch(35.5% 0.115 263.8) |
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 #1B3777 | 11.29:1 | AAA | Lc -99.5 | Preferred for body text |
| Black text on #1B3777 | 1.85:1 | Fails | Lc 8.2 | Not readable |
| #1B3777 text on white | 11.29:1 | AAA | Lc 95.7 | Preferred for body text |
| #1B3777 text on black | 1.85:1 | 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
#F1F6FE
oklch(97.2% 0.012 259.8)
-
Step 100
100
#E1EAFB
oklch(93.5% 0.025 263.3)
-
Step 200
200
#C9DAFA
oklch(88.6% 0.048 263.1)
-
Step 300
300
#A4C1F9
oklch(81% 0.086 263.3)
-
Step 400
400
#749EF6
oklch(70.7% 0.137 263.9)
-
Step 500
500
#5083F3
oklch(63.1% 0.177 263.7)
-
Step 600
600
#3669E1
oklch(55.5% 0.191 263.9)
-
Step 700
700
#2957C4
oklch(49.2% 0.178 263.8)
-
Step 800
800
#22489E
oklch(42.7% 0.147 263.5)
-
Step 900
900 (this color)
#1B3777
oklch(35.5% 0.115 263.8)
-
Step 950
950
#13244A
oklch(26.9% 0.074 264)
#1B3777 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) | #0D3F79 | 0.023 |
| Deuteranopia (no green cones) | #003676 | 0.019 |
| Tritanopia (no blue cones) | #004651 | 0.091 |
| Achromatopsia (no color) | #3A3A3A | 0.115 |
Harmonies
Hue rotations in OKLCH that keep this color's lightness and chroma.
Complementary
The opposite hue (180°).
- #1B3777
#1B3777
oklch(35.5% 0.115 263.8)
- #4E3800
#4E3800
oklch(35.6% 0.073 83.9)
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 #1B3777, closest first.
Similar named colors
The eight closest entries in our named color list, with their ΔE distance.
- Marine Blue #01386A ΔE 0.030
- Twilight Blue #0A437A ΔE 0.034
- Marine #042E60 ΔE 0.053
- Prussian Blue #1D3557 ΔE 0.056
- Cobalt #1E488F ΔE 0.060
- Light Navy #155084 ΔE 0.073
- Midnight Blue #191970 ΔE 0.076
- Dark Grey Blue #29465B ΔE 0.076
Use #1B3777 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.