#6370BC
Closest named color: Windows Blue (#3778BF). oklch(56.9% 0.118 274.7), rgb(99, 112, 188).
Aa
White text reads best on this color (4.59:1).
About this color
#6370BC is a medium-dark, moderately saturated blue. In OKLCH its lightness is 57%, its chroma 0.118 and its hue 275°. Its hue sits on the cool side of the wheel. The nearest named color is Windows Blue (#3778BF), ΔE 0.048 away. White text reads best on it, at 4.59:1.
| Hue family | Blues |
| Lightness | medium-dark (57%) |
| Chroma | moderately saturated (0.118) |
| Temperature | cool |
| Nearest name | Windows Blue (#3778BF) |
| Black text | 4.57:1 |
| White text | 4.59:1 |
Values
| HEX | #6370BC |
| RGB | rgb(99, 112, 188) |
| HSL | hsl(231, 40%, 56%) |
| OKLCH | oklch(56.9% 0.118 274.7) |
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 #6370BC | 4.59:1 | AA | Lc -77.2 | Fine for body text |
| Black text on #6370BC | 4.57:1 | AA | Lc 32.3 | Non-text elements, placeholder text |
| #6370BC text on white | 4.59:1 | AA | Lc 71.8 | Content text, not long reading |
| #6370BC text on black | 4.57:1 | AA | Lc -29.9 | 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
#F4F5FA
oklch(97.1% 0.007 277.2)
-
Step 100
100
#E6E9F4
oklch(93.5% 0.015 273.8)
-
Step 200
200
#D3D8ED
oklch(88.5% 0.029 275.1)
-
Step 300
300
#B6BFE4
oklch(81% 0.053 274.4)
-
Step 400
400
#919DD6
oklch(70.8% 0.085 274.9)
-
Step 500
500
#7684CB
oklch(63.2% 0.108 274.4)
-
Step 600
600 (this color)
#6370BC
oklch(56.9% 0.118 274.7)
-
Step 700
700
#4F5A9E
oklch(49.1% 0.109 274.7)
-
Step 800
800
#414A80
oklch(42.8% 0.09 274.8)
-
Step 900
900
#373E67
oklch(37.8% 0.071 275.1)
-
Step 950
950
#20243C
oklch(26.9% 0.045 275.7)
#6370BC 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) | #5379BF | 0.029 |
| Deuteranopia (no green cones) | #4B72BA | 0.030 |
| Tritanopia (no blue cones) | #42808D | 0.105 |
| Achromatopsia (no color) | #757575 | 0.118 |
Harmonies
Hue rotations in OKLCH that keep this color's lightness and chroma.
Complementary
The opposite hue (180°).
- #6370BC
#6370BC
oklch(56.9% 0.118 274.7)
- #8D7500
#8D7500
oklch(56.8% 0.117 94.6)
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 #6370BC, closest first.
Similar named colors
The eight closest entries in our named color list, with their ΔE distance.
- Windows Blue #3778BF ΔE 0.048
- French Blue #436BAD ΔE 0.049
- Flat Blue #3C73A8 ΔE 0.057
- Dark Periwinkle #665FD1 ΔE 0.058
- Steel Blue #4682B4 ΔE 0.060
- Cool Blue #4984B8 ΔE 0.061
- Slate Blue #6A5ACD ΔE 0.065
- Iris #6258C4 ΔE 0.065
Use #6370BC 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.