#378DE4
Closest named color: Dark Sky Blue (#448EE4). oklch(63.4% 0.154 251.8), rgb(55, 141, 228).
Aa
Black text reads best on this color (6.09:1).
About this color
#378DE4 is a medium-light, vivid blue. In OKLCH its lightness is 63%, its chroma 0.154 and its hue 252°. Its hue sits on the cool side of the wheel. The nearest named color is Dark Sky Blue (#448EE4), ΔE 0.010 away. Black text reads best on it, at 6.09:1.
| Hue family | Blues |
| Lightness | medium-light (63%) |
| Chroma | vivid (0.154) |
| Temperature | cool |
| Nearest name | Dark Sky Blue (#448EE4) |
| Black text | 6.09:1 |
| White text | 3.44:1 |
Values
| HEX | #378DE4 |
| RGB | rgb(55, 141, 228) |
| HSL | hsl(210, 76%, 55%) |
| OKLCH | oklch(63.4% 0.154 251.8) |
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 #378DE4 | 3.44:1 | AA large text | Lc -67.1 | Content text, not long reading |
| Black text on #378DE4 | 6.09:1 | AA | Lc 42.5 | Non-text elements, placeholder text |
| #378DE4 text on white | 3.44:1 | AA large text | Lc 61.6 | Content text, not long reading |
| #378DE4 text on black | 6.09:1 | AA | Lc -40.1 | Non-text elements, placeholder text |
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 500.
-
Step 50
50
#F1F6FC
oklch(97.1% 0.01 252.8)
-
Step 100
100
#E0EBF8
oklch(93.6% 0.021 252.5)
-
Step 200
200
#C6DCF5
oklch(88.6% 0.042 251.7)
-
Step 300
300
#9DC4F1
oklch(80.8% 0.076 252.3)
-
Step 400
400
#66A5EA
oklch(70.8% 0.121 251.9)
-
Step 500
500 (this color)
#378DE4
oklch(63.4% 0.154 251.8)
-
Step 600
600
#0074D0
oklch(55.6% 0.166 251.9)
-
Step 700
700
#0061B0
oklch(49% 0.147 252)
-
Step 800
800
#005091
oklch(42.8% 0.126 251.5)
-
Step 900
900
#0E4375
oklch(37.8% 0.101 251.6)
-
Step 950
950
#0B2744
oklch(26.9% 0.064 252.1)
#378DE4 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) | #6493E8 | 0.045 |
| Deuteranopia (no green cones) | #4983E2 | 0.027 |
| Tritanopia (no blue cones) | #00A2AD | 0.117 |
| Achromatopsia (no color) | #8A8A8A | 0.154 |
Harmonies
Hue rotations in OKLCH that keep this color's lightness and chroma.
Complementary
The opposite hue (180°).
- #378DE4
#378DE4
oklch(63.4% 0.154 251.8)
- #BC7A00
#BC7A00
oklch(63.3% 0.136 71.8)
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 #378DE4, closest first.
Similar named colors
The eight closest entries in our named color list, with their ΔE distance.
- Dark Sky Blue #448EE4 ΔE 0.010
- Chefchaouen Blue #4895EF ΔE 0.030
- Dodger Blue #1E90FF ΔE 0.040
- Soft Blue #6488EA ΔE 0.042
- Water Blue #0E87CC ΔE 0.045
- Cornflower Blue #6495ED ΔE 0.049
- Cool Blue #4984B8 ΔE 0.066
- Clear Blue #247AFD ΔE 0.068
Use #378DE4 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.