#303B89
Closest named color: Cobalt (#1E488F). oklch(39% 0.13 272.8), rgb(48, 59, 137).
Aa
White text reads best on this color (9.94:1).
About this color
#303B89 is a dark, moderately saturated blue. In OKLCH its lightness is 39%, its chroma 0.130 and its hue 273°. Its hue sits on the cool side of the wheel. The nearest named color is Cobalt (#1E488F), ΔE 0.037 away. White text reads best on it, at 9.94:1.
| Hue family | Blues |
| Lightness | dark (39%) |
| Chroma | moderately saturated (0.130) |
| Temperature | cool |
| Nearest name | Cobalt (#1E488F) |
| Black text | 2.11:1 |
| White text | 9.94:1 |
Values
| HEX | #303B89 |
| RGB | rgb(48, 59, 137) |
| HSL | hsl(233, 48%, 36%) |
| OKLCH | oklch(39% 0.13 272.8) |
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 #303B89 | 9.94:1 | AAA | Lc -96.9 | Preferred for body text |
| Black text on #303B89 | 2.11:1 | Fails | Lc 11.2 | Not readable |
| #303B89 text on white | 9.94:1 | AAA | Lc 92.7 | Preferred for body text |
| #303B89 text on black | 2.11:1 | Fails | Lc -9.7 | 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
#F2F5FF
oklch(97.1% 0.014 272.7)
-
Step 100
100
#E3E9FD
oklch(93.5% 0.028 272.5)
-
Step 200
200
#CDD8FE
oklch(88.6% 0.054 272.5)
-
Step 300
300
#ACBDFF
oklch(80.9% 0.095 273)
-
Step 400
400
#8298FF
oklch(70.8% 0.152 272.8)
-
Step 500
500
#6579FF
oklch(63.1% 0.198 273)
-
Step 600
600
#4F5DEF
oklch(55.6% 0.217 272.9)
-
Step 700
700
#414BD0
oklch(49.1% 0.202 273)
-
Step 800
800
#353FA8
oklch(42.7% 0.167 272.9)
-
Step 900
900 (this color)
#303B89
oklch(39% 0.13 272.8)
-
Step 950
950
#1A214E
oklch(27% 0.083 273)
#303B89 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) | #00478C | 0.043 |
| Deuteranopia (no green cones) | #003F87 | 0.038 |
| Tritanopia (no blue cones) | #004E5C | 0.110 |
| Achromatopsia (no color) | #434343 | 0.130 |
Harmonies
Hue rotations in OKLCH that keep this color's lightness and chroma.
Complementary
The opposite hue (180°).
- #303B89
#303B89
oklch(39% 0.13 272.8)
- #544300
#544300
oklch(39% 0.08 92.4)
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 #303B89, closest first.
Similar named colors
The eight closest entries in our named color list, with their ΔE distance.
- Cobalt #1E488F ΔE 0.037
- Dark Slate Blue #483D8B ΔE 0.038
- Blueberry #464196 ΔE 0.044
- Twilight Blue #0A437A ΔE 0.047
- Sapphire #2138AB ΔE 0.059
- Light Navy #155084 ΔE 0.062
- Dusk Blue #26538D ΔE 0.066
- Marine Blue #01386A ΔE 0.071
Use #303B89 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.