#2A3F91
Closest named color: Cobalt (#1E488F). oklch(40.1% 0.138 268.6), rgb(42, 63, 145).
Aa
White text reads best on this color (9.46:1).
About this color
#2A3F91 is a dark, moderately saturated blue. In OKLCH its lightness is 40%, its chroma 0.138 and its hue 269°. Its hue sits on the cool side of the wheel. The nearest named color is Cobalt (#1E488F), ΔE 0.025 away. White text reads best on it, at 9.46:1.
| Hue family | Blues |
| Lightness | dark (40%) |
| Chroma | moderately saturated (0.138) |
| Temperature | cool |
| Nearest name | Cobalt (#1E488F) |
| Black text | 2.21:1 |
| White text | 9.46:1 |
Values
| HEX | #2A3F91 |
| RGB | rgb(42, 63, 145) |
| HSL | hsl(228, 55%, 37%) |
| OKLCH | oklch(40.1% 0.138 268.6) |
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 #2A3F91 | 9.46:1 | AAA | Lc -95.8 | Preferred for body text |
| Black text on #2A3F91 | 2.21:1 | Fails | Lc 12.5 | Not readable |
| #2A3F91 text on white | 9.46:1 | AAA | Lc 91.5 | Preferred for body text |
| #2A3F91 text on black | 2.21:1 | Fails | Lc -10.9 | 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
#F1F5FF
oklch(97% 0.014 268.5)
-
Step 100
100
#E1EAFF
oklch(93.7% 0.03 267.2)
-
Step 200
200
#CAD8FF
oklch(88.4% 0.056 269.7)
-
Step 300
300
#A7BFFF
oklch(81% 0.095 268.4)
-
Step 400
400
#799AFF
oklch(70.6% 0.153 268.6)
-
Step 500
500
#597DFF
oklch(63.2% 0.197 268.6)
-
Step 600
600
#3F5EF7
oklch(55.6% 0.23 268.7)
-
Step 700
700
#324CD7
oklch(49.1% 0.213 268.6)
-
Step 800
800
#2940AE
oklch(42.8% 0.177 268.5)
-
Step 900
900 (this color)
#2A3F91
oklch(40.1% 0.138 268.6)
-
Step 950
950
#152250
oklch(27.1% 0.086 268.3)
#2A3F91 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) | #004B94 | 0.037 |
| Deuteranopia (no green cones) | #00418F | 0.029 |
| Tritanopia (no blue cones) | #005361 | 0.113 |
| Achromatopsia (no color) | #464646 | 0.138 |
Harmonies
Hue rotations in OKLCH that keep this color's lightness and chroma.
Complementary
The opposite hue (180°).
- #2A3F91
#2A3F91
oklch(40.1% 0.138 268.6)
- #5A4500
#5A4500
oklch(40.2% 0.082 88.8)
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 #2A3F91, closest first.
Similar named colors
The eight closest entries in our named color list, with their ΔE distance.
- Cobalt #1E488F ΔE 0.025
- Blueberry #464196 ΔE 0.041
- Dark Slate Blue #483D8B ΔE 0.044
- Sapphire #2138AB ΔE 0.047
- Twilight Blue #0A437A ΔE 0.049
- Light Navy #155084 ΔE 0.056
- Dusk Blue #26538D ΔE 0.057
- Deep Sea Blue #015482 ΔE 0.069
Use #2A3F91 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.