#378CB3
Closest named color: Blue NCS (#118AB2). oklch(60.6% 0.1 231.7), rgb(55, 140, 179).
Aa
Black text reads best on this color (5.56:1).
About this color
#378CB3 is a medium-dark, moderately saturated blue. In OKLCH its lightness is 61%, its chroma 0.100 and its hue 232°. Its hue sits on the cool side of the wheel. The nearest named color is Blue NCS (#118AB2), ΔE 0.019 away. Black text reads best on it, at 5.56:1.
| Hue family | Blues |
| Lightness | medium-dark (61%) |
| Chroma | moderately saturated (0.100) |
| Temperature | cool |
| Nearest name | Blue NCS (#118AB2) |
| Black text | 5.56:1 |
| White text | 3.77:1 |
Values
| HEX | #378CB3 |
| RGB | rgb(55, 140, 179) |
| HSL | hsl(199, 53%, 46%) |
| OKLCH | oklch(60.6% 0.1 231.7) |
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 #378CB3 | 3.77:1 | AA large text | Lc -70.5 | Content text, not long reading |
| Black text on #378CB3 | 5.56:1 | AA | Lc 39.1 | Non-text elements, placeholder text |
| #378CB3 text on white | 3.77:1 | AA large text | Lc 65.0 | Content text, not long reading |
| #378CB3 text on black | 5.56:1 | AA | Lc -36.7 | 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
#A2C7DB
oklch(80.9% 0.049 231.7)
-
Step 400
400
#6CAAC9
oklch(70.8% 0.078 231.1)
-
Step 500
500 (this color)
#378CB3
oklch(60.6% 0.1 231.7)
-
Step 600
600
#127DA7
oklch(55.5% 0.108 231.9)
-
Step 700
700
#006A8F
oklch(49.2% 0.1 231.3)
-
Step 800
800
#095674
oklch(42.6% 0.083 231.7)
-
Step 900
900
#15475E
oklch(37.6% 0.065 232.4)
-
Step 950
950
#0E2A37
oklch(27% 0.041 231.2)
#378CB3 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) | #798AB5 | 0.067 |
| Deuteranopia (no green cones) | #677EB2 | 0.056 |
| Tritanopia (no blue cones) | #009799 | 0.062 |
| Achromatopsia (no color) | #838383 | 0.100 |
Harmonies
Hue rotations in OKLCH that keep this color's lightness and chroma.
Complementary
The opposite hue (180°).
- #378CB3
#378CB3
oklch(60.6% 0.1 231.7)
- #B17047
#B17047
oklch(60.6% 0.1 52.1)
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 #378CB3, closest first.
Similar named colors
The eight closest entries in our named color list, with their ΔE distance.
- Blue NCS #118AB2 ΔE 0.019
- Cool Blue #4984B8 ΔE 0.029
- Steel Blue #4682B4 ΔE 0.030
- Off Blue #5684AE ΔE 0.031
- Dusty Blue #5A86AD ΔE 0.032
- Teal Blue #01889F ΔE 0.041
- Faded Blue #658CBB ΔE 0.046
- Water Blue #0E87CC ΔE 0.047
Use #378CB3 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.