#1F377E
Closest named color: Twilight Blue (#0A437A). oklch(36.3% 0.124 266.2), rgb(31, 55, 126).
Aa
White text reads best on this color (11.01:1).
About this color
#1F377E is a dark, moderately saturated blue. In OKLCH its lightness is 36%, its chroma 0.124 and its hue 266°. Its hue sits on the cool side of the wheel. The nearest named color is Twilight Blue (#0A437A), ΔE 0.036 away. White text reads best on it, at 11.01:1.
| Hue family | Blues |
| Lightness | dark (36%) |
| Chroma | moderately saturated (0.124) |
| Temperature | cool |
| Nearest name | Twilight Blue (#0A437A) |
| Black text | 1.90:1 |
| White text | 11.01:1 |
Values
| HEX | #1F377E |
| RGB | rgb(31, 55, 126) |
| HSL | hsl(225, 61%, 31%) |
| OKLCH | oklch(36.3% 0.124 266.2) |
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 #1F377E | 11.01:1 | AAA | Lc -99.0 | Preferred for body text |
| Black text on #1F377E | 1.90:1 | Fails | Lc 8.8 | Not readable |
| #1F377E text on white | 11.01:1 | AAA | Lc 95.1 | Preferred for body text |
| #1F377E text on black | 1.90:1 | Fails | Lc -7.5 | 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
#C9D9FC
oklch(88.5% 0.051 265.9)
-
Step 300
300
#A5C0FE
oklch(81% 0.093 266.2)
-
Step 400
400
#759CFD
oklch(70.7% 0.149 266.1)
-
Step 500
500
#5380FB
oklch(63.2% 0.19 266)
-
Step 600
600
#3A65EA
oklch(55.6% 0.207 266.1)
-
Step 700
700
#2D53CC
oklch(49.2% 0.192 266)
-
Step 800
800
#2645A5
oklch(42.8% 0.159 266.1)
-
Step 900
900 (this color)
#1F377E
oklch(36.3% 0.124 266.2)
-
Step 950
950
#14234C
oklch(26.9% 0.078 266.1)
#1F377E 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) | #004180 | 0.030 |
| Deuteranopia (no green cones) | #00387D | 0.021 |
| Tritanopia (no blue cones) | #004855 | 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°).
- #1F377E
#1F377E
oklch(36.3% 0.124 266.2)
- #4F3A00
#4F3A00
oklch(36.2% 0.074 85.7)
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 #1F377E, closest first.
Similar named colors
The eight closest entries in our named color list, with their ΔE distance.
- Twilight Blue #0A437A ΔE 0.036
- Marine Blue #01386A ΔE 0.042
- Cobalt #1E488F ΔE 0.053
- Marine #042E60 ΔE 0.064
- Dark Slate Blue #483D8B ΔE 0.067
- Prussian Blue #1D3557 ΔE 0.068
- Light Navy #155084 ΔE 0.071
- Sapphire #2138AB ΔE 0.075
Use #1F377E 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.