#378BB1
Closest named color: Blue NCS (#118AB2). oklch(60.2% 0.098 231.3), rgb(55, 139, 177).
Aa
Black text reads best on this color (5.49:1).
About this color
#378BB1 is a medium-dark, moderately saturated blue. In OKLCH its lightness is 60%, its chroma 0.098 and its hue 231°. Its hue sits on the cool side of the wheel. The nearest named color is Blue NCS (#118AB2), ΔE 0.018 away. Black text reads best on it, at 5.49:1.
| Hue family | Blues |
| Lightness | medium-dark (60%) |
| Chroma | moderately saturated (0.098) |
| Temperature | cool |
| Nearest name | Blue NCS (#118AB2) |
| Black text | 5.49:1 |
| White text | 3.82:1 |
Values
| HEX | #378BB1 |
| RGB | rgb(55, 139, 177) |
| HSL | hsl(199, 53%, 45%) |
| OKLCH | oklch(60.2% 0.098 231.3) |
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 #378BB1 | 3.82:1 | AA large text | Lc -71.0 | Content text, not long reading |
| Black text on #378BB1 | 5.49:1 | AA | Lc 38.6 | Non-text elements, placeholder text |
| #378BB1 text on white | 3.82:1 | AA large text | Lc 65.5 | Content text, not long reading |
| #378BB1 text on black | 5.49:1 | AA | Lc -36.2 | 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
#F1F6F9
oklch(97% 0.007 233.6)
-
Step 100
100
#E1ECF2
oklch(93.7% 0.014 231.2)
-
Step 200
200
#C8DDE8
oklch(88.5% 0.027 230.4)
-
Step 300
300
#A2C7DA
oklch(80.9% 0.048 230.4)
-
Step 400
400
#6DAAC8
oklch(70.8% 0.077 230.6)
-
Step 500
500 (this color)
#378BB1
oklch(60.2% 0.098 231.3)
-
Step 600
600
#157EA6
oklch(55.7% 0.106 230.6)
-
Step 700
700
#006A8F
oklch(49.2% 0.1 231.3)
-
Step 800
800
#0B5674
oklch(42.6% 0.083 231.9)
-
Step 900
900
#15475D
oklch(37.6% 0.064 231.2)
-
Step 950
950
#0F2A37
oklch(27.1% 0.041 231.9)
#378BB1 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) | #7889B3 | 0.067 |
| Deuteranopia (no green cones) | #677DB0 | 0.057 |
| Tritanopia (no blue cones) | #009598 | 0.059 |
| Achromatopsia (no color) | #828282 | 0.098 |
Harmonies
Hue rotations in OKLCH that keep this color's lightness and chroma.
Complementary
The opposite hue (180°).
- #378BB1
#378BB1
oklch(60.2% 0.098 231.3)
- #AF6F48
#AF6F48
oklch(60.2% 0.098 51.3)
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 #378BB1, closest first.
Similar named colors
The eight closest entries in our named color list, with their ΔE distance.
- Blue NCS #118AB2 ΔE 0.018
- Cool Blue #4984B8 ΔE 0.028
- Steel Blue #4682B4 ΔE 0.029
- Off Blue #5684AE ΔE 0.030
- Dusty Blue #5A86AD ΔE 0.031
- Teal Blue #01889F ΔE 0.038
- Faded Blue #658CBB ΔE 0.047
- Cerulean #457B9D ΔE 0.048
Use #378BB1 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.