#304289
Closest named color: Cobalt (#1E488F). oklch(40.5% 0.12 269.7), rgb(48, 66, 137).
Aa
White text reads best on this color (9.26:1).
About this color
#304289 is a dark, moderately saturated blue. In OKLCH its lightness is 40%, its chroma 0.120 and its hue 270°. Its hue sits on the cool side of the wheel. The nearest named color is Cobalt (#1E488F), ΔE 0.023 away. White text reads best on it, at 9.26:1.
| Hue family | Blues |
| Lightness | dark (40%) |
| Chroma | moderately saturated (0.120) |
| Temperature | cool |
| Nearest name | Cobalt (#1E488F) |
| Black text | 2.26:1 |
| White text | 9.26:1 |
Values
| HEX | #304289 |
| RGB | rgb(48, 66, 137) |
| HSL | hsl(228, 48%, 36%) |
| OKLCH | oklch(40.5% 0.12 269.7) |
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 #304289 | 9.26:1 | AAA | Lc -95.5 | Preferred for body text |
| Black text on #304289 | 2.26:1 | Fails | Lc 12.9 | Not readable |
| #304289 text on white | 9.26:1 | AAA | Lc 91.1 | Preferred for body text |
| #304289 text on black | 2.26:1 | Fails | Lc -11.2 | 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 800.
-
Step 50
50
#F3F5FC
oklch(97.1% 0.01 273.4)
-
Step 100
100
#E4EAF8
oklch(93.7% 0.02 267.3)
-
Step 200
200
#CFD9F4
oklch(88.6% 0.039 269.4)
-
Step 300
300
#AEBFEF
oklch(80.8% 0.071 269.6)
-
Step 400
400
#859DE7
oklch(70.7% 0.112 269.7)
-
Step 500
500
#6783E0
oklch(63.2% 0.144 269.4)
-
Step 600
600
#506ACE
oklch(55.6% 0.157 269.7)
-
Step 700
700
#4158B2
oklch(49.1% 0.145 269.6)
-
Step 800
800 (this color)
#304289
oklch(40.5% 0.12 269.7)
-
Step 900
900
#2E3D73
oklch(37.6% 0.094 269.8)
-
Step 950
950
#1B2443
oklch(26.9% 0.059 269.9)
#304289 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) | #1A4B8C | 0.029 |
| Deuteranopia (no green cones) | #024388 | 0.035 |
| Tritanopia (no blue cones) | #00525F | 0.101 |
| Achromatopsia (no color) | #474747 | 0.120 |
Harmonies
Hue rotations in OKLCH that keep this color's lightness and chroma.
Complementary
The opposite hue (180°).
- #304289
#304289
oklch(40.5% 0.12 269.7)
- #5B4600
#5B4600
oklch(40.5% 0.083 89.1)
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 #304289, closest first.
Similar named colors
The eight closest entries in our named color list, with their ΔE distance.
- Cobalt #1E488F ΔE 0.023
- Dark Slate Blue #483D8B ΔE 0.036
- Blueberry #464196 ΔE 0.039
- Twilight Blue #0A437A ΔE 0.043
- Light Navy #155084 ΔE 0.045
- Dusk Blue #26538D ΔE 0.047
- Deep Sea Blue #015482 ΔE 0.060
- Twilight #4E518B ΔE 0.064
Use #304289 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.