#373F63
Closest named color: Dark Grey Blue (#29465B). oklch(37.7% 0.063 273.5), rgb(55, 63, 99).
Aa
White text reads best on this color (10.22:1).
About this color
#373F63 is a dark, muted blue. In OKLCH its lightness is 38%, its chroma 0.063 and its hue 274°. Its hue sits on the cool side of the wheel. The nearest named color is Dark Grey Blue (#29465B), ΔE 0.034 away. White text reads best on it, at 10.22:1.
| Hue family | Blues |
| Lightness | dark (38%) |
| Chroma | muted (0.063) |
| Temperature | cool |
| Nearest name | Dark Grey Blue (#29465B) |
| Black text | 2.05:1 |
| White text | 10.22:1 |
Values
| HEX | #373F63 |
| RGB | rgb(55, 63, 99) |
| HSL | hsl(229, 29%, 30%) |
| OKLCH | oklch(37.7% 0.063 273.5) |
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 #373F63 | 10.22:1 | AAA | Lc -97.7 | Preferred for body text |
| Black text on #373F63 | 2.05:1 | Fails | Lc 10.2 | Not readable |
| #373F63 text on white | 10.22:1 | AAA | Lc 93.7 | Preferred for body text |
| #373F63 text on black | 2.05:1 | Fails | Lc -8.8 | 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 900.
-
Step 50
50
#F4F5FA
oklch(97.1% 0.007 277.2)
-
Step 100
100
#E7E9F3
oklch(93.5% 0.014 277.1)
-
Step 200
200
#D3D8EB
oklch(88.4% 0.027 274.1)
-
Step 300
300
#B6BFE0
oklch(80.8% 0.048 273.3)
-
Step 400
400
#919ED0
oklch(70.7% 0.075 273.1)
-
Step 500
500
#7785C4
oklch(63.1% 0.096 273.8)
-
Step 600
600
#606EB0
oklch(55.6% 0.104 273.5)
-
Step 700
700
#4F5C98
oklch(49.2% 0.097 273.1)
-
Step 800
800
#414B7B
oklch(42.7% 0.081 273.6)
-
Step 900
900 (this color)
#373F63
oklch(37.7% 0.063 273.5)
-
Step 950
950
#20253A
oklch(27% 0.04 273.2)
#373F63 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) | #334364 | 0.013 |
| Deuteranopia (no green cones) | #2F3F62 | 0.012 |
| Tritanopia (no blue cones) | #29464C | 0.055 |
| Achromatopsia (no color) | #414141 | 0.063 |
Harmonies
Hue rotations in OKLCH that keep this color's lightness and chroma.
Complementary
The opposite hue (180°).
- #373F63
#373F63
oklch(37.7% 0.063 273.5)
- #4D4116
#4D4116
oklch(37.8% 0.062 93.5)
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 #373F63, closest first.
Similar named colors
The eight closest entries in our named color list, with their ΔE distance.
- Dark Grey Blue #29465B ΔE 0.034
- Charcoal #264653 ΔE 0.046
- Dark Blue Grey #1F3B4D ΔE 0.053
- Prussian Blue #1D3557 ΔE 0.053
- Twilight Blue #0A437A ΔE 0.055
- Charcoal Grey #3C4142 ΔE 0.060
- Onyx #343A40 ΔE 0.060
- Marine Blue #01386A ΔE 0.062
Use #373F63 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.