#3978AC
Closest named color: Flat Blue (#3C73A8). oklch(55.5% 0.104 246.1), rgb(57, 120, 172).
Aa
White text reads best on this color (4.71:1).
About this color
#3978AC is a medium-dark, moderately saturated blue. In OKLCH its lightness is 55%, its chroma 0.104 and its hue 246°. Its hue sits on the cool side of the wheel. The nearest named color is Flat Blue (#3C73A8), ΔE 0.014 away. White text reads best on it, at 4.71:1.
| Hue family | Blues |
| Lightness | medium-dark (55%) |
| Chroma | moderately saturated (0.104) |
| Temperature | cool |
| Nearest name | Flat Blue (#3C73A8) |
| Black text | 4.45:1 |
| White text | 4.71:1 |
Values
| HEX | #3978AC |
| RGB | rgb(57, 120, 172) |
| HSL | hsl(207, 50%, 45%) |
| OKLCH | oklch(55.5% 0.104 246.1) |
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 #3978AC | 4.71:1 | AA | Lc -77.9 | Fine for body text |
| Black text on #3978AC | 4.45:1 | AA large text | Lc 31.6 | Non-text elements, placeholder text |
| #3978AC text on white | 4.71:1 | AA | Lc 72.5 | Content text, not long reading |
| #3978AC text on black | 4.45:1 | AA large text | Lc -29.2 | 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
#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
#7AA6CD
oklch(70.8% 0.075 245.9)
-
Step 500
500
#568FC0
oklch(63.1% 0.096 246)
-
Step 600
600 (this color)
#3978AC
oklch(55.5% 0.104 246.1)
-
Step 700
700
#2B6594
oklch(49.1% 0.097 246.1)
-
Step 800
800
#255378
oklch(42.8% 0.08 245.5)
-
Step 900
900
#234561
oklch(37.8% 0.063 245.4)
-
Step 950
950
#152839
oklch(26.9% 0.04 246.9)
#3978AC 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) | #617AAE | 0.044 |
| Deuteranopia (no green cones) | #516EAB | 0.034 |
| Tritanopia (no blue cones) | #00848A | 0.078 |
| Achromatopsia (no color) | #737373 | 0.104 |
Harmonies
Hue rotations in OKLCH that keep this color's lightness and chroma.
Complementary
The opposite hue (180°).
- #3978AC
#3978AC
oklch(55.5% 0.104 246.1)
- #9C6527
#9C6527
oklch(55.5% 0.104 65.5)
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 #3978AC, closest first.
Similar named colors
The eight closest entries in our named color list, with their ΔE distance.
- Flat Blue #3C73A8 ΔE 0.014
- Nice Blue #107AB0 ΔE 0.021
- Muted Blue #3B719F ΔE 0.025
- Dull Blue #49759C ΔE 0.027
- Cerulean #457B9D ΔE 0.029
- Windows Blue #3778BF ΔE 0.030
- Steel Blue #4682B4 ΔE 0.033
- Stormy Blue #507B9C ΔE 0.036
Use #3978AC 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.