#378AE9
Closest named color: Dark Sky Blue (#448EE4). oklch(63% 0.164 254.3), rgb(55, 138, 233).
Aa
Black text reads best on this color (5.97:1).
About this color
#378AE9 is a medium-light, vivid blue. In OKLCH its lightness is 63%, its chroma 0.164 and its hue 254°. Its hue sits on the cool side of the wheel. The nearest named color is Dark Sky Blue (#448EE4), ΔE 0.018 away. Black text reads best on it, at 5.97:1.
| Hue family | Blues |
| Lightness | medium-light (63%) |
| Chroma | vivid (0.164) |
| Temperature | cool |
| Nearest name | Dark Sky Blue (#448EE4) |
| Black text | 5.97:1 |
| White text | 3.51:1 |
Values
| HEX | #378AE9 |
| RGB | rgb(55, 138, 233) |
| HSL | hsl(212, 80%, 56%) |
| OKLCH | oklch(63% 0.164 254.3) |
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 #378AE9 | 3.51:1 | AA large text | Lc -67.8 | Content text, not long reading |
| Black text on #378AE9 | 5.97:1 | AA | Lc 41.8 | Non-text elements, placeholder text |
| #378AE9 text on white | 3.51:1 | AA large text | Lc 62.3 | Content text, not long reading |
| #378AE9 text on black | 5.97:1 | AA | Lc -39.4 | 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
#F1F6FD
oklch(97.1% 0.011 256.7)
-
Step 100
100
#E0EBFA
oklch(93.6% 0.024 256.1)
-
Step 200
200
#C6DBF7
oklch(88.5% 0.045 255.6)
-
Step 300
300
#9DC4F4
oklch(80.9% 0.08 253.9)
-
Step 400
400
#66A3EF
oklch(70.6% 0.129 254.7)
-
Step 500
500 (this color)
#378AE9
oklch(63% 0.164 254.3)
-
Step 600
600
#0172D7
oklch(55.6% 0.177 254)
-
Step 700
700
#005FB7
oklch(49.1% 0.158 254.4)
-
Step 800
800
#004E97
oklch(42.8% 0.136 254.1)
-
Step 900
900
#0F4178
oklch(37.6% 0.107 254.4)
-
Step 950
950
#0B2746
oklch(27% 0.067 253.4)
#378AE9 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) | #5C91ED | 0.039 |
| Deuteranopia (no green cones) | #3D81E7 | 0.023 |
| Tritanopia (no blue cones) | #00A0AE | 0.123 |
| Achromatopsia (no color) | #898989 | 0.164 |
Harmonies
Hue rotations in OKLCH that keep this color's lightness and chroma.
Complementary
The opposite hue (180°).
- #378AE9
#378AE9
oklch(63% 0.164 254.3)
- #B87B00
#B87B00
oklch(63% 0.133 74.4)
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 #378AE9, closest first.
Similar named colors
The eight closest entries in our named color list, with their ΔE distance.
- Dark Sky Blue #448EE4 ΔE 0.018
- Dodger Blue #1E90FF ΔE 0.034
- Chefchaouen Blue #4895EF ΔE 0.034
- Soft Blue #6488EA ΔE 0.040
- Water Blue #0E87CC ΔE 0.050
- Cornflower Blue #6495ED ΔE 0.053
- Clear Blue #247AFD ΔE 0.056
- Cornflower #6A79F7 ΔE 0.066
Use #378AE9 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.