#303B64
Closest named color: Prussian Blue (#1D3557). oklch(36.3% 0.072 271.1), rgb(48, 59, 100).
Aa
White text reads best on this color (10.85:1).
About this color
#303B64 is a dark, moderately saturated blue. In OKLCH its lightness is 36%, its chroma 0.072 and its hue 271°. Its hue sits on the cool side of the wheel. The nearest named color is Prussian Blue (#1D3557), ΔE 0.040 away. White text reads best on it, at 10.85:1.
| Hue family | Blues |
| Lightness | dark (36%) |
| Chroma | moderately saturated (0.072) |
| Temperature | cool |
| Nearest name | Prussian Blue (#1D3557) |
| Black text | 1.93:1 |
| White text | 10.85:1 |
Values
| HEX | #303B64 |
| RGB | rgb(48, 59, 100) |
| HSL | hsl(227, 35%, 29%) |
| OKLCH | oklch(36.3% 0.072 271.1) |
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 #303B64 | 10.85:1 | AAA | Lc -98.9 | Preferred for body text |
| Black text on #303B64 | 1.93:1 | Fails | Lc 8.9 | Not readable |
| #303B64 text on white | 10.85:1 | AAA | Lc 95.0 | Preferred for body text |
| #303B64 text on black | 1.93:1 | Fails | Lc -7.6 | 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
#F3F5FA
oklch(97% 0.007 268.5)
-
Step 100
100
#E6EAF5
oklch(93.7% 0.015 270)
-
Step 200
200
#D1D9EE
oklch(88.6% 0.03 269.1)
-
Step 300
300
#B3BFE5
oklch(80.8% 0.055 271.4)
-
Step 400
400
#8C9ED7
oklch(70.7% 0.086 270.6)
-
Step 500
500
#7185CD
oklch(63.2% 0.111 271.1)
-
Step 600
600
#5A6DBA
oklch(55.6% 0.122 271.5)
-
Step 700
700
#4A5BA0
oklch(49.1% 0.112 271.3)
-
Step 800
800
#3C4B82
oklch(42.8% 0.093 270.6)
-
Step 900
900 (this color)
#303B64
oklch(36.3% 0.072 271.1)
-
Step 950
950
#1E253D
oklch(27% 0.046 270.7)
#303B64 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) | #2B3F66 | 0.013 |
| Deuteranopia (no green cones) | #263B63 | 0.014 |
| Tritanopia (no blue cones) | #1B444A | 0.066 |
| Achromatopsia (no color) | #3D3D3D | 0.072 |
Harmonies
Hue rotations in OKLCH that keep this color's lightness and chroma.
Complementary
The opposite hue (180°).
- #303B64
#303B64
oklch(36.3% 0.072 271.1)
- #4C3C03
#4C3C03
oklch(36.3% 0.072 91.3)
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 #303B64, closest first.
Similar named colors
The eight closest entries in our named color list, with their ΔE distance.
- Prussian Blue #1D3557 ΔE 0.040
- Dark Grey Blue #29465B ΔE 0.042
- Marine Blue #01386A ΔE 0.047
- Dark Blue Grey #1F3B4D ΔE 0.048
- Twilight Blue #0A437A ΔE 0.049
- Charcoal #264653 ΔE 0.053
- Midnight Green #073B4C ΔE 0.062
- Onyx #343A40 ΔE 0.063
Use #303B64 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.