#1F3881
Closest named color: Twilight Blue (#0A437A). oklch(36.8% 0.127 266), rgb(31, 56, 129).
Aa
White text reads best on this color (10.81:1).
About this color
#1F3881 is a dark, moderately saturated blue. In OKLCH its lightness is 37%, its chroma 0.127 and its hue 266°. 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 10.81:1.
| Hue family | Blues |
| Lightness | dark (37%) |
| Chroma | moderately saturated (0.127) |
| Temperature | cool |
| Nearest name | Twilight Blue (#0A437A) |
| Black text | 1.94:1 |
| White text | 10.81:1 |
Values
| HEX | #1F3881 |
| RGB | rgb(31, 56, 129) |
| HSL | hsl(225, 61%, 31%) |
| OKLCH | oklch(36.8% 0.127 266) |
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 #1F3881 | 10.81:1 | AAA | Lc -98.6 | Preferred for body text |
| Black text on #1F3881 | 1.94:1 | Fails | Lc 9.3 | Not readable |
| #1F3881 text on white | 10.81:1 | AAA | Lc 94.6 | Preferred for body text |
| #1F3881 text on black | 1.94:1 | Fails | Lc -8.0 | 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
#F1F5FE
oklch(97% 0.013 266.7)
-
Step 100
100
#E1EAFD
oklch(93.6% 0.028 265.4)
-
Step 200
200
#C9D9FD
oklch(88.5% 0.053 266.4)
-
Step 300
300
#A4C0FF
oklch(81% 0.095 265.8)
-
Step 400
400
#749CFF
oklch(70.8% 0.152 266)
-
Step 500
500
#517FFE
oklch(63.1% 0.196 266)
-
Step 600
600
#3864ED
oklch(55.6% 0.212 266)
-
Step 700
700
#2B52CE
oklch(49.1% 0.197 265.9)
-
Step 800
800
#2444A7
oklch(42.7% 0.164 265.9)
-
Step 900
900 (this color)
#1F3881
oklch(36.8% 0.127 266)
-
Step 950
950
#14234D
oklch(27% 0.08 266.3)
#1F3881 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) | #004284 | 0.030 |
| Deuteranopia (no green cones) | #003980 | 0.021 |
| Tritanopia (no blue cones) | #004A56 | 0.102 |
| Achromatopsia (no color) | #3D3D3D | 0.127 |
Harmonies
Hue rotations in OKLCH that keep this color's lightness and chroma.
Complementary
The opposite hue (180°).
- #1F3881
#1F3881
oklch(36.8% 0.127 266)
- #513B00
#513B00
oklch(36.7% 0.075 84.9)
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 #1F3881, 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 0.047
- Cobalt #1E488F ΔE 0.048
- Dark Slate Blue #483D8B ΔE 0.064
- Light Navy #155084 ΔE 0.068
- Marine #042E60 ΔE 0.069
- Sapphire #2138AB ΔE 0.070
- Blueberry #464196 ΔE 0.071
Use #1F3881 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.