#3378AA
Closest named color: Flat Blue (#3C73A8). oklch(55.2% 0.104 243.4), rgb(51, 120, 170).
Aa
White text reads best on this color (4.76:1).
About this color
#3378AA is a medium-dark, moderately saturated blue. In OKLCH its lightness is 55%, its chroma 0.104 and its hue 243°. Its hue sits on the cool side of the wheel. The nearest named color is Flat Blue (#3C73A8), ΔE 0.015 away. White text reads best on it, at 4.76:1.
| Hue family | Blues |
| Lightness | medium-dark (55%) |
| Chroma | moderately saturated (0.104) |
| Temperature | cool |
| Nearest name | Flat Blue (#3C73A8) |
| Black text | 4.40:1 |
| White text | 4.76:1 |
Values
| HEX | #3378AA |
| RGB | rgb(51, 120, 170) |
| HSL | hsl(205, 54%, 43%) |
| OKLCH | oklch(55.2% 0.104 243.4) |
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 #3378AA | 4.76:1 | AA | Lc -78.2 | Fine for body text |
| Black text on #3378AA | 4.40:1 | AA large text | Lc 31.3 | Non-text elements, placeholder text |
| #3378AA text on white | 4.76:1 | AA | Lc 72.8 | Content text, not long reading |
| #3378AA text on black | 4.40:1 | AA large text | Lc -28.9 | Dividers and decoration only |
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
#F2F6F9
oklch(97.1% 0.006 239.8)
-
Step 100
100
#E2EBF2
oklch(93.5% 0.014 241)
-
Step 200
200
#CBDCE9
oklch(88.6% 0.026 240.7)
-
Step 300
300
#A7C5DD
oklch(80.9% 0.047 242.4)
-
Step 400
400
#77A6CC
oklch(70.6% 0.075 243.5)
-
Step 500
500
#5290BF
oklch(63.1% 0.096 243)
-
Step 600
600 (this color)
#3378AA
oklch(55.2% 0.104 243.4)
-
Step 700
700
#266693
oklch(49.1% 0.097 243.1)
-
Step 800
800
#225377
oklch(42.6% 0.08 243.6)
-
Step 900
900
#214560
oklch(37.7% 0.062 243.2)
-
Step 950
950
#142938
oklch(27.1% 0.039 241.3)
#3378AA 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) | #6179AC | 0.048 |
| Deuteranopia (no green cones) | #516EA9 | 0.037 |
| Tritanopia (no blue cones) | #00848A | 0.074 |
| Achromatopsia (no color) | #737373 | 0.104 |
Harmonies
Hue rotations in OKLCH that keep this color's lightness and chroma.
Complementary
The opposite hue (180°).
- #3378AA
#3378AA
oklch(55.2% 0.104 243.4)
- #9C6328
#9C6328
oklch(55.1% 0.104 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 #3378AA, closest first.
Similar named colors
The eight closest entries in our named color list, with their ΔE distance.
- Flat Blue #3C73A8 ΔE 0.015
- Nice Blue #107AB0 ΔE 0.018
- Muted Blue #3B719F ΔE 0.023
- Dull Blue #49759C ΔE 0.027
- Cerulean #457B9D ΔE 0.029
- Windows Blue #3778BF ΔE 0.034
- Stormy Blue #507B9C ΔE 0.037
- Steel Blue #4682B4 ΔE 0.037
Use #3378AA 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.