#378BF0
Closest named color: Dark Sky Blue (#448EE4). oklch(63.7% 0.171 255.2), rgb(55, 139, 240).
Aa
Black text reads best on this color (6.11:1).
About this color
#378BF0 is a medium-light, vivid blue. In OKLCH its lightness is 64%, its chroma 0.171 and its hue 255°. Its hue sits on the cool side of the wheel. The nearest named color is Dark Sky Blue (#448EE4), ΔE 0.023 away. Black text reads best on it, at 6.11:1.
| Hue family | Blues |
| Lightness | medium-light (64%) |
| Chroma | vivid (0.171) |
| Temperature | cool |
| Nearest name | Dark Sky Blue (#448EE4) |
| Black text | 6.11:1 |
| White text | 3.43:1 |
Values
| HEX | #378BF0 |
| RGB | rgb(55, 139, 240) |
| HSL | hsl(213, 86%, 58%) |
| OKLCH | oklch(63.7% 0.171 255.2) |
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 #378BF0 | 3.43:1 | AA large text | Lc -66.9 | Content text, not long reading |
| Black text on #378BF0 | 6.11:1 | AA | Lc 42.6 | Non-text elements, placeholder text |
| #378BF0 text on white | 3.43:1 | AA large text | Lc 61.4 | Content text, not long reading |
| #378BF0 text on black | 6.11:1 | AA | Lc -40.3 | 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
#DFEBFA
oklch(93.6% 0.024 254)
-
Step 200
200
#C5DBF8
oklch(88.4% 0.047 255.4)
-
Step 300
300
#9CC4F7
oklch(81% 0.084 254.7)
-
Step 400
400
#64A3F2
oklch(70.7% 0.134 254.9)
-
Step 500
500 (this color)
#378BF0
oklch(63.7% 0.171 255.2)
-
Step 600
600
#0070DB
oklch(55.5% 0.184 255.3)
-
Step 700
700
#005EBA
oklch(49.1% 0.163 255.3)
-
Step 800
800
#004D9A
oklch(42.7% 0.142 255.2)
-
Step 900
900
#0E417B
oklch(37.8% 0.111 255.1)
-
Step 950
950
#0B2648
oklch(26.9% 0.071 255.8)
#378BF0 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) | #5993F4 | 0.038 |
| Deuteranopia (no green cones) | #3783EE | 0.021 |
| Tritanopia (no blue cones) | #00A3B2 | 0.130 |
| Achromatopsia (no color) | #8A8A8A | 0.171 |
Harmonies
Hue rotations in OKLCH that keep this color's lightness and chroma.
Complementary
The opposite hue (180°).
- #378BF0
#378BF0
oklch(63.7% 0.171 255.2)
- #BA7D00
#BA7D00
oklch(63.7% 0.134 74.8)
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 #378BF0, closest first.
Similar named colors
The eight closest entries in our named color list, with their ΔE distance.
- Dark Sky Blue #448EE4 ΔE 0.023
- Dodger Blue #1E90FF ΔE 0.025
- Chefchaouen Blue #4895EF ΔE 0.032
- Soft Blue #6488EA ΔE 0.039
- Cornflower Blue #6495ED ΔE 0.051
- Clear Blue #247AFD ΔE 0.053
- Water Blue #0E87CC ΔE 0.060
- Cornflower #6A79F7 ΔE 0.063
Use #378BF0 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.