#378FCC
Closest named color: Water Blue (#0E87CC). oklch(62.5% 0.124 242.9), rgb(55, 143, 204).
Aa
Black text reads best on this color (5.96:1).
About this color
#378FCC is a medium-light, moderately saturated blue. In OKLCH its lightness is 63%, its chroma 0.124 and its hue 243°. Its hue sits on the cool side of the wheel. The nearest named color is Water Blue (#0E87CC), ΔE 0.031 away. Black text reads best on it, at 5.96:1.
| Hue family | Blues |
| Lightness | medium-light (63%) |
| Chroma | moderately saturated (0.124) |
| Temperature | cool |
| Nearest name | Water Blue (#0E87CC) |
| Black text | 5.96:1 |
| White text | 3.52:1 |
Values
| HEX | #378FCC |
| RGB | rgb(55, 143, 204) |
| HSL | hsl(205, 59%, 51%) |
| OKLCH | oklch(62.5% 0.124 242.9) |
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 #378FCC | 3.52:1 | AA large text | Lc -67.9 | Content text, not long reading |
| Black text on #378FCC | 5.96:1 | AA | Lc 41.6 | Non-text elements, placeholder text |
| #378FCC text on white | 3.52:1 | AA large text | Lc 62.5 | Content text, not long reading |
| #378FCC text on black | 5.96:1 | AA | Lc -39.2 | 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
#F1F6FB
oklch(97.1% 0.009 247.9)
-
Step 100
100
#E0ECF5
oklch(93.7% 0.018 240)
-
Step 200
200
#C7DCEE
oklch(88.4% 0.034 244)
-
Step 300
300
#9FC6E5
oklch(80.9% 0.061 242.5)
-
Step 400
400
#68A8D8
oklch(70.7% 0.097 242.3)
-
Step 500
500 (this color)
#378FCC
oklch(62.5% 0.124 242.9)
-
Step 600
600
#007ABB
oklch(55.7% 0.134 242.9)
-
Step 700
700
#00669E
oklch(49% 0.119 243.2)
-
Step 800
800
#005482
oklch(42.8% 0.102 242.4)
-
Step 900
900
#104669
oklch(37.8% 0.081 242.5)
-
Step 950
950
#0C293D
oklch(27% 0.051 242.2)
#378FCC 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) | #7390CF | 0.058 |
| Deuteranopia (no green cones) | #5E82CB | 0.045 |
| Tritanopia (no blue cones) | #009EA4 | 0.087 |
| Achromatopsia (no color) | #888888 | 0.124 |
Harmonies
Hue rotations in OKLCH that keep this color's lightness and chroma.
Complementary
The opposite hue (180°).
- #378FCC
#378FCC
oklch(62.5% 0.124 242.9)
- #BB752A
#BB752A
oklch(62.5% 0.124 63.2)
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 #378FCC, closest first.
Similar named colors
The eight closest entries in our named color list, with their ΔE distance.
- Water Blue #0E87CC ΔE 0.031
- Cool Blue #4984B8 ΔE 0.038
- Dark Sky Blue #448EE4 ΔE 0.039
- Faded Blue #658CBB ΔE 0.045
- Steel Blue #4682B4 ΔE 0.045
- Blue NCS #118AB2 ΔE 0.046
- Off Blue #5684AE ΔE 0.051
- Dusty Blue #5A86AD ΔE 0.052
Use #378FCC 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.