#378DC3
Closest named color: Cool Blue (#4984B8). oklch(61.6% 0.115 240.2), rgb(55, 141, 195).
Aa
Black text reads best on this color (5.76:1).
About this color
#378DC3 is a medium-dark, moderately saturated blue. In OKLCH its lightness is 62%, its chroma 0.115 and its hue 240°. Its hue sits on the cool side of the wheel. The nearest named color is Cool Blue (#4984B8), ΔE 0.028 away. Black text reads best on it, at 5.76:1.
| Hue family | Blues |
| Lightness | medium-dark (62%) |
| Chroma | moderately saturated (0.115) |
| Temperature | cool |
| Nearest name | Cool Blue (#4984B8) |
| Black text | 5.76:1 |
| White text | 3.64:1 |
Values
| HEX | #378DC3 |
| RGB | rgb(55, 141, 195) |
| HSL | hsl(203, 56%, 49%) |
| OKLCH | oklch(61.6% 0.115 240.2) |
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 #378DC3 | 3.64:1 | AA large text | Lc -69.2 | Content text, not long reading |
| Black text on #378DC3 | 5.76:1 | AA | Lc 40.3 | Non-text elements, placeholder text |
| #378DC3 text on white | 3.64:1 | AA large text | Lc 63.7 | Content text, not long reading |
| #378DC3 text on black | 5.76:1 | AA | Lc -37.9 | 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
#F1F6FA
oklch(97.1% 0.008 241.7)
-
Step 100
100
#E1ECF4
oklch(93.7% 0.016 239.1)
-
Step 200
200
#C7DCEC
oklch(88.4% 0.032 240.7)
-
Step 300
300
#A0C6E2
oklch(80.8% 0.057 240.3)
-
Step 400
400
#6AA8D3
oklch(70.6% 0.09 240)
-
Step 500
500 (this color)
#378DC3
oklch(61.6% 0.115 240.2)
-
Step 600
600
#097BB5
oklch(55.6% 0.126 240.3)
-
Step 700
700
#00679A
oklch(49.1% 0.113 240.5)
-
Step 800
800
#04547E
oklch(42.6% 0.097 240.6)
-
Step 900
900
#124665
oklch(37.7% 0.075 239.9)
-
Step 950
950
#0D293B
oklch(26.9% 0.047 240.1)
#378DC3 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) | #748DC5 | 0.060 |
| Deuteranopia (no green cones) | #6180C2 | 0.048 |
| Tritanopia (no blue cones) | #009BA0 | 0.079 |
| Achromatopsia (no color) | #868686 | 0.115 |
Harmonies
Hue rotations in OKLCH that keep this color's lightness and chroma.
Complementary
The opposite hue (180°).
- #378DC3
#378DC3
oklch(61.6% 0.115 240.2)
- #B77334
#B77334
oklch(61.7% 0.116 60.5)
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 #378DC3, closest first.
Similar named colors
The eight closest entries in our named color list, with their ΔE distance.
- Cool Blue #4984B8 ΔE 0.028
- Water Blue #0E87CC ΔE 0.031
- Steel Blue #4682B4 ΔE 0.034
- Blue NCS #118AB2 ΔE 0.034
- Off Blue #5684AE ΔE 0.040
- Dusty Blue #5A86AD ΔE 0.041
- Faded Blue #658CBB ΔE 0.042
- Dark Sky Blue #448EE4 ΔE 0.052
Use #378DC3 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.