#397CCE
Closest named color: Windows Blue (#3778BF). oklch(58.4% 0.143 255.1), rgb(57, 124, 206).
Aa
Black text reads best on this color (4.94:1).
About this color
#397CCE is a medium-dark, vivid blue. In OKLCH its lightness is 58%, its chroma 0.143 and its hue 255°. Its hue sits on the cool side of the wheel. The nearest named color is Windows Blue (#3778BF), ΔE 0.024 away. Black text reads best on it, at 4.94:1.
| Hue family | Blues |
| Lightness | medium-dark (58%) |
| Chroma | vivid (0.143) |
| Temperature | cool |
| Nearest name | Windows Blue (#3778BF) |
| Black text | 4.94:1 |
| White text | 4.24:1 |
Values
| HEX | #397CCE |
| RGB | rgb(57, 124, 206) |
| HSL | hsl(213, 60%, 52%) |
| OKLCH | oklch(58.4% 0.143 255.1) |
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 #397CCE | 4.24:1 | AA large text | Lc -74.5 | Content text, not long reading |
| Black text on #397CCE | 4.94:1 | AA | Lc 35.1 | Non-text elements, placeholder text |
| #397CCE text on white | 4.24:1 | AA large text | Lc 69.0 | Content text, not long reading |
| #397CCE text on black | 4.94:1 | AA | Lc -32.7 | 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
#E2EBF7
oklch(93.7% 0.019 255.5)
-
Step 200
200
#CADBF1
oklch(88.6% 0.035 254.9)
-
Step 300
300
#A5C3EA
oklch(80.8% 0.064 255.1)
-
Step 400
400
#74A3E0
oklch(70.6% 0.103 255.3)
-
Step 500
500
#4E8BD7
oklch(63% 0.132 254.9)
-
Step 600
600 (this color)
#397CCE
oklch(58.4% 0.143 255.1)
-
Step 700
700
#2360AA
oklch(49% 0.134 255.4)
-
Step 800
800
#1F4F8A
oklch(42.7% 0.111 255.4)
-
Step 900
900
#1F426E
oklch(37.7% 0.086 255.3)
-
Step 950
950
#132740
oklch(27% 0.054 254.9)
#397CCE 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) | #5582D1 | 0.033 |
| Deuteranopia (no green cones) | #3E75CC | 0.018 |
| Tritanopia (no blue cones) | #008F9B | 0.110 |
| Achromatopsia (no color) | #7B7B7B | 0.143 |
Harmonies
Hue rotations in OKLCH that keep this color's lightness and chroma.
Complementary
The opposite hue (180°).
- #397CCE
#397CCE
oklch(58.4% 0.143 255.1)
- #A56F00
#A56F00
oklch(58.4% 0.123 75.3)
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 #397CCE, closest first.
Similar named colors
The eight closest entries in our named color list, with their ΔE distance.
- Windows Blue #3778BF ΔE 0.024
- Water Blue #0E87CC ΔE 0.034
- Cool Blue #4984B8 ΔE 0.047
- Steel Blue #4682B4 ΔE 0.048
- Nice Blue #107AB0 ΔE 0.054
- Dark Sky Blue #448EE4 ΔE 0.057
- Flat Blue #3C73A8 ΔE 0.060
- Royal Blue #4169E1 ΔE 0.060
Use #397CCE 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.