#397CCB
Closest named color: Windows Blue (#3778BF). oklch(58.2% 0.139 254.3), rgb(57, 124, 203).
Aa
Black text reads best on this color (4.91:1).
About this color
#397CCB is a medium-dark, moderately saturated blue. In OKLCH its lightness is 58%, its chroma 0.139 and its hue 254°. Its hue sits on the cool side of the wheel. The nearest named color is Windows Blue (#3778BF), ΔE 0.020 away. Black text reads best on it, at 4.91:1.
| Hue family | Blues |
| Lightness | medium-dark (58%) |
| Chroma | moderately saturated (0.139) |
| Temperature | cool |
| Nearest name | Windows Blue (#3778BF) |
| Black text | 4.91:1 |
| White text | 4.26:1 |
Values
| HEX | #397CCB |
| RGB | rgb(57, 124, 203) |
| HSL | hsl(212, 58%, 51%) |
| OKLCH | oklch(58.2% 0.139 254.3) |
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 #397CCB | 4.26:1 | AA large text | Lc -74.7 | Content text, not long reading |
| Black text on #397CCB | 4.91:1 | AA | Lc 34.9 | Non-text elements, placeholder text |
| #397CCB text on white | 4.26:1 | AA large text | Lc 69.2 | Content text, not long reading |
| #397CCB text on black | 4.91:1 | AA | Lc -32.5 | Non-text elements, placeholder text |
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
#F2F6FB
oklch(97.2% 0.008 253.9)
-
Step 100
100
#E2EBF6
oklch(93.7% 0.018 253.3)
-
Step 200
200
#CADBF0
oklch(88.5% 0.034 253.7)
-
Step 300
300
#A5C3E9
oklch(80.8% 0.063 254.5)
-
Step 400
400
#74A4DE
oklch(70.8% 0.1 253.7)
-
Step 500
500
#4F8CD5
oklch(63.2% 0.128 254.1)
-
Step 600
600 (this color)
#397CCB
oklch(58.2% 0.139 254.3)
-
Step 700
700
#2361A8
oklch(49.1% 0.13 254.4)
-
Step 800
800
#1F5088
oklch(42.8% 0.107 254)
-
Step 900
900
#1F426D
oklch(37.6% 0.085 254.8)
-
Step 950
950
#132740
oklch(27% 0.054 254.9)
#397CCB 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) | #5782CE | 0.035 |
| Deuteranopia (no green cones) | #4174C9 | 0.021 |
| Tritanopia (no blue cones) | #008E9A | 0.106 |
| Achromatopsia (no color) | #7A7A7A | 0.139 |
Harmonies
Hue rotations in OKLCH that keep this color's lightness and chroma.
Complementary
The opposite hue (180°).
- #397CCB
#397CCB
oklch(58.2% 0.139 254.3)
- #A56E00
#A56E00
oklch(58.2% 0.123 74.5)
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 #397CCB, closest first.
Similar named colors
The eight closest entries in our named color list, with their ΔE distance.
- Windows Blue #3778BF ΔE 0.020
- Water Blue #0E87CC ΔE 0.033
- Cool Blue #4984B8 ΔE 0.044
- Steel Blue #4682B4 ΔE 0.044
- Nice Blue #107AB0 ΔE 0.050
- Flat Blue #3C73A8 ΔE 0.056
- French Blue #436BAD ΔE 0.059
- Dark Sky Blue #448EE4 ΔE 0.059
Use #397CCB 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.