#2A3781
Closest named color: Twilight Blue (#0A437A). oklch(37.1% 0.125 271.4), rgb(42, 55, 129).
Aa
White text reads best on this color (10.70:1).
About this color
#2A3781 is a dark, moderately saturated blue. In OKLCH its lightness is 37%, its chroma 0.125 and its hue 271°. Its hue sits on the cool side of the wheel. The nearest named color is Twilight Blue (#0A437A), ΔE 0.042 away. White text reads best on it, at 10.70:1.
| Hue family | Blues |
| Lightness | dark (37%) |
| Chroma | moderately saturated (0.125) |
| Temperature | cool |
| Nearest name | Twilight Blue (#0A437A) |
| Black text | 1.96:1 |
| White text | 10.70:1 |
Values
| HEX | #2A3781 |
| RGB | rgb(42, 55, 129) |
| HSL | hsl(231, 51%, 34%) |
| OKLCH | oklch(37.1% 0.125 271.4) |
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 #2A3781 | 10.70:1 | AAA | Lc -98.4 | Preferred for body text |
| Black text on #2A3781 | 1.96:1 | Fails | Lc 9.4 | Not readable |
| #2A3781 text on white | 10.70:1 | AAA | Lc 94.5 | Preferred for body text |
| #2A3781 text on black | 1.96:1 | Fails | Lc -8.1 | 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
#F2F5FE
oklch(97% 0.012 271.3)
-
Step 100
100
#E3E9FD
oklch(93.5% 0.028 272.5)
-
Step 200
200
#CCD8FD
oklch(88.5% 0.053 271.1)
-
Step 300
300
#AABEFE
oklch(81% 0.094 270.8)
-
Step 400
400
#7F99FE
oklch(70.8% 0.151 271.2)
-
Step 500
500
#627BFB
oklch(63% 0.192 271.5)
-
Step 600
600
#4C60EB
oklch(55.6% 0.209 271.5)
-
Step 700
700
#3E4ECC
oklch(49.1% 0.194 271.6)
-
Step 800
800
#3241A5
oklch(42.7% 0.161 271.3)
-
Step 900
900 (this color)
#2A3781
oklch(37.1% 0.125 271.4)
-
Step 950
950
#19224D
oklch(27.1% 0.08 271.2)
#2A3781 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 | 0.039 |
| Deuteranopia (no green cones) | #003A80 | 0.033 |
| Tritanopia (no blue cones) | #004956 | 0.105 |
| Achromatopsia (no color) | #3E3E3E | 0.125 |
Harmonies
Hue rotations in OKLCH that keep this color's lightness and chroma.
Complementary
The opposite hue (180°).
- #2A3781
#2A3781
oklch(37.1% 0.125 271.4)
- #4F3E00
#4F3E00
oklch(37.1% 0.076 91.2)
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 #2A3781, closest first.
Similar named colors
The eight closest entries in our named color list, with their ΔE distance.
- Twilight Blue #0A437A ΔE 0.042
- Cobalt #1E488F ΔE 0.049
- Dark Slate Blue #483D8B ΔE 0.053
- Marine Blue #01386A ΔE 0.055
- Blueberry #464196 ΔE 0.062
- Sapphire #2138AB ΔE 0.070
- Light Navy #155084 ΔE 0.070
- Marine #042E60 ΔE 0.076
Use #2A3781 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.