#3978AE
Closest named color: Flat Blue (#3C73A8). oklch(55.6% 0.106 247), rgb(57, 120, 174).
Aa
White text reads best on this color (4.69:1).
About this color
#3978AE is a medium-dark, moderately saturated blue. In OKLCH its lightness is 56%, its chroma 0.106 and its hue 247°. 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 4.69:1.
| Hue family | Blues |
| Lightness | medium-dark (56%) |
| Chroma | moderately saturated (0.106) |
| Temperature | cool |
| Nearest name | Flat Blue (#3C73A8) |
| Black text | 4.47:1 |
| White text | 4.69:1 |
Values
| HEX | #3978AE |
| RGB | rgb(57, 120, 174) |
| HSL | hsl(208, 51%, 45%) |
| OKLCH | oklch(55.6% 0.106 247) |
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 #3978AE | 4.69:1 | AA | Lc -77.8 | Fine for body text |
| Black text on #3978AE | 4.47:1 | AA large text | Lc 31.7 | Non-text elements, placeholder text |
| #3978AE text on white | 4.69:1 | AA | Lc 72.4 | Content text, not long reading |
| #3978AE text on black | 4.47:1 | AA large text | Lc -29.3 | 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
#F2F6FA
oklch(97.1% 0.007 247.9)
-
Step 100
100
#E3EBF3
oklch(93.6% 0.014 248)
-
Step 200
200
#CCDBEA
oklch(88.5% 0.026 248.1)
-
Step 300
300
#A9C4DE
oklch(80.9% 0.047 247.4)
-
Step 400
400
#79A5CE
oklch(70.6% 0.077 247.2)
-
Step 500
500
#568FC2
oklch(63.2% 0.098 247)
-
Step 600
600 (this color)
#3978AE
oklch(55.6% 0.106 247)
-
Step 700
700
#2B6596
oklch(49.2% 0.099 247.1)
-
Step 800
800
#255279
oklch(42.6% 0.082 247.3)
-
Step 900
900
#234462
oklch(37.6% 0.065 247.8)
-
Step 950
950
#152839
oklch(26.9% 0.04 246.9)
#3978AE 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) | #607AB0 | 0.043 |
| Deuteranopia (no green cones) | #506FAD | 0.031 |
| Tritanopia (no blue cones) | #00858B | 0.081 |
| Achromatopsia (no color) | #747474 | 0.106 |
Harmonies
Hue rotations in OKLCH that keep this color's lightness and chroma.
Complementary
The opposite hue (180°).
- #3978AE
#3978AE
oklch(55.6% 0.106 247)
- #9C6623
#9C6623
oklch(55.6% 0.106 67.6)
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 #3978AE, 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 0.021
- Windows Blue #3778BF ΔE 0.027
- Muted Blue #3B719F ΔE 0.027
- Dull Blue #49759C ΔE 0.029
- Cerulean #457B9D ΔE 0.032
- Steel Blue #4682B4 ΔE 0.033
- French Blue #436BAD ΔE 0.037
Use #3978AE 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.