#303C99
Closest named color: Sapphire (#2138AB). oklch(40.5% 0.151 272.2), rgb(48, 60, 153).
Aa
White text reads best on this color (9.40:1).
About this color
#303C99 is a dark, vivid blue. In OKLCH its lightness is 41%, its chroma 0.151 and its hue 272°. Its hue sits on the cool side of the wheel. The nearest named color is Sapphire (#2138AB), ΔE 0.036 away. White text reads best on it, at 9.40:1.
| Hue family | Blues |
| Lightness | dark (41%) |
| Chroma | vivid (0.151) |
| Temperature | cool |
| Nearest name | Sapphire (#2138AB) |
| Black text | 2.23:1 |
| White text | 9.40:1 |
Values
| HEX | #303C99 |
| RGB | rgb(48, 60, 153) |
| HSL | hsl(233, 52%, 39%) |
| OKLCH | oklch(40.5% 0.151 272.2) |
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 #303C99 | 9.40:1 | AAA | Lc -95.6 | Preferred for body text |
| Black text on #303C99 | 2.23:1 | Fails | Lc 12.7 | Not readable |
| #303C99 text on white | 9.40:1 | AAA | Lc 91.3 | Preferred for body text |
| #303C99 text on black | 2.23:1 | Fails | Lc -11.1 | 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
#F2F5FE
oklch(97% 0.012 271.3)
-
Step 100
100
#E4E9FC
oklch(93.6% 0.026 274.1)
-
Step 200
200
#CDD8FA
oklch(88.5% 0.048 271.2)
-
Step 300
300
#ADBEFA
oklch(81% 0.087 272.1)
-
Step 400
400
#8299F8
oklch(70.6% 0.141 272.1)
-
Step 500
500
#667DF5
oklch(63.2% 0.18 272.1)
-
Step 600
600
#4F62E4
oklch(55.6% 0.197 272.1)
-
Step 700
700
#4150C6
oklch(49.1% 0.183 272.3)
-
Step 800
800 (this color)
#303C99
oklch(40.5% 0.151 272.2)
-
Step 900
900
#2D397F
oklch(37.6% 0.118 272.1)
-
Step 950
950
#1A224A
oklch(26.9% 0.075 272)
#303C99 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) | #004B9C | 0.045 |
| Deuteranopia (no green cones) | #004297 | 0.036 |
| Tritanopia (no blue cones) | #005364 | 0.124 |
| Achromatopsia (no color) | #464646 | 0.152 |
Harmonies
Hue rotations in OKLCH that keep this color's lightness and chroma.
Complementary
The opposite hue (180°).
- #303C99
#303C99
oklch(40.5% 0.151 272.2)
- #594700
#594700
oklch(40.5% 0.083 92.2)
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 #303C99, closest first.
Similar named colors
The eight closest entries in our named color list, with their ΔE distance.
- Sapphire #2138AB ΔE 0.036
- Blueberry #464196 ΔE 0.037
- Cobalt #1E488F ΔE 0.039
- Dark Slate Blue #483D8B ΔE 0.043
- Twilight Blue #0A437A ΔE 0.065
- Dusk Blue #26538D ΔE 0.067
- Light Navy #155084 ΔE 0.070
- Indigo Blue #3A18B1 ΔE 0.070
Use #303C99 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.