#3378CC
Closest named color: Windows Blue (#3778BF). oklch(57.1% 0.147 255.2), rgb(51, 120, 204).
Aa
Black text reads best on this color (4.69:1).
About this color
#3378CC is a medium-dark, vivid blue. In OKLCH its lightness is 57%, its chroma 0.147 and its hue 255°. Its hue sits on the cool side of the wheel. The nearest named color is Windows Blue (#3778BF), ΔE 0.020 away. Black text reads best on it, at 4.69:1.
| Hue family | Blues |
| Lightness | medium-dark (57%) |
| Chroma | vivid (0.147) |
| Temperature | cool |
| Nearest name | Windows Blue (#3778BF) |
| Black text | 4.69:1 |
| White text | 4.46:1 |
Values
| HEX | #3378CC |
| RGB | rgb(51, 120, 204) |
| HSL | hsl(213, 60%, 50%) |
| OKLCH | oklch(57.1% 0.147 255.2) |
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 #3378CC | 4.46:1 | AA large text | Lc -76.1 | Fine for body text |
| Black text on #3378CC | 4.69:1 | AA | Lc 33.4 | Non-text elements, placeholder text |
| #3378CC text on white | 4.46:1 | AA large text | Lc 70.6 | Content text, not long reading |
| #3378CC text on black | 4.69:1 | AA | Lc -31.0 | 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 600.
-
Step 50
50
#F2F6FB
oklch(97.2% 0.008 253.9)
-
Step 100
100
#E2EBF7
oklch(93.7% 0.019 255.5)
-
Step 200
200
#C9DBF2
oklch(88.5% 0.037 254.6)
-
Step 300
300
#A4C3EB
oklch(80.8% 0.066 254.9)
-
Step 400
400
#73A3E2
oklch(70.7% 0.106 255.6)
-
Step 500
500
#4D8BD9
oklch(63.1% 0.135 255.1)
-
Step 600
600 (this color)
#3378CC
oklch(57.1% 0.147 255.2)
-
Step 700
700
#2060AC
oklch(49% 0.137 255.3)
-
Step 800
800
#1D4F8B
oklch(42.7% 0.113 255.1)
-
Step 900
900
#1E426F
oklch(37.7% 0.088 255.3)
-
Step 950
950
#122741
oklch(27% 0.056 254.8)
#3378CC 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) | #4F7FCF | 0.034 |
| Deuteranopia (no green cones) | #3571CA | 0.019 |
| Tritanopia (no blue cones) | #008C98 | 0.113 |
| Achromatopsia (no color) | #777777 | 0.147 |
Harmonies
Hue rotations in OKLCH that keep this color's lightness and chroma.
Complementary
The opposite hue (180°).
- #3378CC
#3378CC
oklch(57.1% 0.147 255.2)
- #A06C00
#A06C00
oklch(57.2% 0.12 75.7)
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 #3378CC, closest first.
Similar named colors
The eight closest entries in our named color list, with their ΔE distance.
- Windows Blue #3778BF ΔE 0.020
- Water Blue #0E87CC ΔE 0.042
- Nice Blue #107AB0 ΔE 0.050
- Mid Blue #276AB3 ΔE 0.053
- Royal Blue #4169E1 ΔE 0.054
- French Blue #436BAD ΔE 0.054
- Steel Blue #4682B4 ΔE 0.054
- Cool Blue #4984B8 ΔE 0.055
Use #3378CC 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.