#304B9E
Closest named color: Cobalt (#1E488F). oklch(44% 0.139 267), rgb(48, 75, 158).
Aa
White text reads best on this color (7.99:1).
About this color
#304B9E is a dark, moderately saturated blue. In OKLCH its lightness is 44%, its chroma 0.139 and its hue 267°. Its hue sits on the cool side of the wheel. The nearest named color is Cobalt (#1E488F), ΔE 0.033 away. White text reads best on it, at 7.99:1.
| Hue family | Blues |
| Lightness | dark (44%) |
| Chroma | moderately saturated (0.139) |
| Temperature | cool |
| Nearest name | Cobalt (#1E488F) |
| Black text | 2.62:1 |
| White text | 7.99:1 |
Values
| HEX | #304B9E |
| RGB | rgb(48, 75, 158) |
| HSL | hsl(225, 53%, 40%) |
| OKLCH | oklch(44% 0.139 267) |
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 #304B9E | 7.99:1 | AAA | Lc -92.1 | Preferred for body text |
| Black text on #304B9E | 2.62:1 | Fails | Lc 16.6 | Dividers and decoration only |
| #304B9E text on white | 7.99:1 | AAA | Lc 87.4 | Fine for body text |
| #304B9E text on black | 2.62:1 | Fails | Lc -14.8 | 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
#F2F5FD
oklch(97% 0.011 269.6)
-
Step 100
100
#E3EAFA
oklch(93.6% 0.023 266.9)
-
Step 200
200
#CCD9F8
oklch(88.5% 0.045 267.4)
-
Step 300
300
#A9C0F6
oklch(81% 0.081 266.7)
-
Step 400
400
#7C9DF2
oklch(70.7% 0.13 267)
-
Step 500
500
#5C82ED
oklch(63.1% 0.166 266.9)
-
Step 600
600
#4469DB
oklch(55.7% 0.179 266.9)
-
Step 700
700
#3656BE
oklch(49% 0.168 267)
-
Step 800
800 (this color)
#304B9E
oklch(44% 0.139 267)
-
Step 900
900
#283D7A
oklch(37.8% 0.107 266.9)
-
Step 950
950
#172448
oklch(27% 0.069 266.8)
#304B9E 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) | #1756A1 | 0.032 |
| Deuteranopia (no green cones) | #004C9C | 0.031 |
| Tritanopia (no blue cones) | #005F6D | 0.114 |
| Achromatopsia (no color) | #515151 | 0.139 |
Harmonies
Hue rotations in OKLCH that keep this color's lightness and chroma.
Complementary
The opposite hue (180°).
- #304B9E
#304B9E
oklch(44% 0.139 267)
- #684E00
#684E00
oklch(43.9% 0.09 86.4)
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 #304B9E, closest first.
Similar named colors
The eight closest entries in our named color list, with their ΔE distance.
- Cobalt #1E488F ΔE 0.033
- Blueberry #464196 ΔE 0.037
- Dusk Blue #26538D ΔE 0.039
- Dark Slate Blue #483D8B ΔE 0.052
- Light Navy #155084 ΔE 0.053
- Denim Blue #3B5B92 ΔE 0.055
- Twilight #4E518B ΔE 0.055
- Sapphire #2138AB ΔE 0.056
Use #304B9E 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.