#397AAB
Closest named color: Flat Blue (#3C73A8). oklch(55.9% 0.101 243.9), rgb(57, 122, 171).
Aa
White text reads best on this color (4.61:1).
About this color
#397AAB is a medium-dark, moderately saturated blue. In OKLCH its lightness is 56%, its chroma 0.101 and its hue 244°. Its hue sits on the cool side of the wheel. The nearest named color is Flat Blue (#3C73A8), ΔE 0.020 away. White text reads best on it, at 4.61:1.
| Hue family | Blues |
| Lightness | medium-dark (56%) |
| Chroma | moderately saturated (0.101) |
| Temperature | cool |
| Nearest name | Flat Blue (#3C73A8) |
| Black text | 4.54:1 |
| White text | 4.61:1 |
Values
| HEX | #397AAB |
| RGB | rgb(57, 122, 171) |
| HSL | hsl(206, 50%, 45%) |
| OKLCH | oklch(55.9% 0.101 243.9) |
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 #397AAB | 4.61:1 | AA | Lc -77.3 | Fine for body text |
| Black text on #397AAB | 4.54:1 | AA | Lc 32.2 | Non-text elements, placeholder text |
| #397AAB text on white | 4.61:1 | AA | Lc 71.9 | Content text, not long reading |
| #397AAB text on black | 4.54:1 | AA | Lc -29.8 | 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
#A8C5DC
oklch(80.9% 0.045 242.1)
-
Step 400
400
#79A6CB
oklch(70.7% 0.073 243.9)
-
Step 500
500
#5590BE
oklch(63.2% 0.093 243.5)
-
Step 600
600 (this color)
#397AAB
oklch(55.9% 0.101 243.9)
-
Step 700
700
#2A6692
oklch(49.2% 0.094 243.7)
-
Step 800
800
#245376
oklch(42.7% 0.078 243.6)
-
Step 900
900
#23455F
oklch(37.7% 0.06 243.4)
-
Step 950
950
#152838
oklch(26.9% 0.039 245.4)
#397AAB 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) | #647BAD | 0.047 |
| Deuteranopia (no green cones) | #5470AA | 0.036 |
| Tritanopia (no blue cones) | #00868B | 0.075 |
| Achromatopsia (no color) | #757575 | 0.101 |
Harmonies
Hue rotations in OKLCH that keep this color's lightness and chroma.
Complementary
The opposite hue (180°).
- #397AAB
#397AAB
oklch(55.9% 0.101 243.9)
- #9D662D
#9D662D
oklch(55.9% 0.101 63.8)
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 #397AAB, closest first.
Similar named colors
The eight closest entries in our named color list, with their ΔE distance.
- Flat Blue #3C73A8 ΔE 0.020
- Nice Blue #107AB0 ΔE 0.022
- Cerulean #457B9D ΔE 0.025
- Dull Blue #49759C ΔE 0.026
- Muted Blue #3B719F ΔE 0.028
- Steel Blue #4682B4 ΔE 0.029
- Stormy Blue #507B9C ΔE 0.032
- Windows Blue #3778BF ΔE 0.033
Use #397AAB 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.