#3978AA
Closest named color: Flat Blue (#3C73A8). oklch(55.4% 0.101 245.1), rgb(57, 120, 170).
Aa
White text reads best on this color (4.72:1).
About this color
#3978AA is a medium-dark, moderately saturated blue. In OKLCH its lightness is 55%, its chroma 0.101 and its hue 245°. 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 4.72:1.
| Hue family | Blues |
| Lightness | medium-dark (55%) |
| Chroma | moderately saturated (0.101) |
| Temperature | cool |
| Nearest name | Flat Blue (#3C73A8) |
| Black text | 4.44:1 |
| White text | 4.72:1 |
Values
| HEX | #3978AA |
| RGB | rgb(57, 120, 170) |
| HSL | hsl(207, 50%, 45%) |
| OKLCH | oklch(55.4% 0.101 245.1) |
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 #3978AA | 4.72:1 | AA | Lc -78.0 | Fine for body text |
| Black text on #3978AA | 4.44:1 | AA large text | Lc 31.5 | Non-text elements, placeholder text |
| #3978AA text on white | 4.72:1 | AA | Lc 72.6 | Content text, not long reading |
| #3978AA text on black | 4.44:1 | AA large text | Lc -29.1 | 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
#E3EBF2
oklch(93.6% 0.013 244.3)
-
Step 200
200
#CCDBE9
oklch(88.4% 0.025 246.2)
-
Step 300
300
#A9C4DD
oklch(80.8% 0.046 246.3)
-
Step 400
400
#7AA6CC
oklch(70.8% 0.073 245.2)
-
Step 500
500
#568FBE
oklch(63% 0.093 244.9)
-
Step 600
600 (this color)
#3978AA
oklch(55.4% 0.101 245.1)
-
Step 700
700
#2B6593
oklch(49% 0.095 245.5)
-
Step 800
800
#255377
oklch(42.7% 0.078 244.8)
-
Step 900
900
#244560
oklch(37.8% 0.061 245.1)
-
Step 950
950
#152838
oklch(26.9% 0.039 245.4)
#3978AA 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) | #6279AC | 0.045 |
| Deuteranopia (no green cones) | #526EA9 | 0.035 |
| Tritanopia (no blue cones) | #00848A | 0.075 |
| Achromatopsia (no color) | #737373 | 0.101 |
Harmonies
Hue rotations in OKLCH that keep this color's lightness and chroma.
Complementary
The opposite hue (180°).
- #3978AA
#3978AA
oklch(55.4% 0.101 245.1)
- #9B652A
#9B652A
oklch(55.4% 0.101 65)
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 #3978AA, 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 0.022
- Muted Blue #3B719F ΔE 0.023
- Dull Blue #49759C ΔE 0.024
- Cerulean #457B9D ΔE 0.026
- Windows Blue #3778BF ΔE 0.033
- Stormy Blue #507B9C ΔE 0.034
- Steel Blue #4682B4 ΔE 0.034
Use #3978AA 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.