#378BC9
Closest named color: Water Blue (#0E87CC). oklch(61.4% 0.124 244.3), rgb(55, 139, 201).
Aa
Black text reads best on this color (5.69:1).
About this color
#378BC9 is a medium-dark, moderately saturated blue. In OKLCH its lightness is 61%, its chroma 0.124 and its hue 244°. Its hue sits on the cool side of the wheel. The nearest named color is Water Blue (#0E87CC), ΔE 0.023 away. Black text reads best on it, at 5.69:1.
| Hue family | Blues |
| Lightness | medium-dark (61%) |
| Chroma | moderately saturated (0.124) |
| Temperature | cool |
| Nearest name | Water Blue (#0E87CC) |
| Black text | 5.69:1 |
| White text | 3.68:1 |
Values
| HEX | #378BC9 |
| RGB | rgb(55, 139, 201) |
| HSL | hsl(205, 57%, 50%) |
| OKLCH | oklch(61.4% 0.124 244.3) |
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 #378BC9 | 3.68:1 | AA large text | Lc -69.6 | Content text, not long reading |
| Black text on #378BC9 | 5.69:1 | AA | Lc 40.0 | Non-text elements, placeholder text |
| #378BC9 text on white | 3.68:1 | AA large text | Lc 64.1 | Content text, not long reading |
| #378BC9 text on black | 5.69:1 | AA | Lc -37.6 | 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
#F1F6FB
oklch(97.1% 0.009 247.9)
-
Step 100
100
#E1EBF5
oklch(93.5% 0.017 248)
-
Step 200
200
#C7DCEE
oklch(88.4% 0.034 244)
-
Step 300
300
#A0C6E5
oklch(81% 0.06 243.2)
-
Step 400
400
#6AA7D9
oklch(70.7% 0.097 244.5)
-
Step 500
500 (this color)
#378BC9
oklch(61.4% 0.124 244.3)
-
Step 600
600
#0D79BC
oklch(55.6% 0.135 244.6)
-
Step 700
700
#0066A0
oklch(49.2% 0.121 244)
-
Step 800
800
#055383
oklch(42.7% 0.104 244.4)
-
Step 900
900
#134569
oklch(37.7% 0.081 244.5)
-
Step 950
950
#0D293D
oklch(27% 0.05 242.9)
#378BC9 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) | #6F8DCC | 0.055 |
| Deuteranopia (no green cones) | #5A7FC8 | 0.041 |
| Tritanopia (no blue cones) | #009AA1 | 0.088 |
| Achromatopsia (no color) | #858585 | 0.124 |
Harmonies
Hue rotations in OKLCH that keep this color's lightness and chroma.
Complementary
The opposite hue (180°).
- #378BC9
#378BC9
oklch(61.4% 0.124 244.3)
- #B77225
#B77225
oklch(61.4% 0.124 63.9)
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 #378BC9, closest first.
Similar named colors
The eight closest entries in our named color list, with their ΔE distance.
- Water Blue #0E87CC ΔE 0.023
- Cool Blue #4984B8 ΔE 0.029
- Steel Blue #4682B4 ΔE 0.036
- Blue NCS #118AB2 ΔE 0.042
- Dark Sky Blue #448EE4 ΔE 0.043
- Off Blue #5684AE ΔE 0.045
- Faded Blue #658CBB ΔE 0.046
- Dusty Blue #5A86AD ΔE 0.048
Use #378BC9 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.