#6370CB
Closest named color: Dark Periwinkle (#665FD1). oklch(57.8% 0.14 275), rgb(99, 112, 203).
Aa
Black text reads best on this color (4.71:1).
About this color
#6370CB is a medium-dark, moderately saturated blue. In OKLCH its lightness is 58%, its chroma 0.140 and its hue 275°. Its hue sits on the cool side of the wheel. The nearest named color is Dark Periwinkle (#665FD1), ΔE 0.044 away. Black text reads best on it, at 4.71:1.
| Hue family | Blues |
| Lightness | medium-dark (58%) |
| Chroma | moderately saturated (0.140) |
| Temperature | cool |
| Nearest name | Dark Periwinkle (#665FD1) |
| Black text | 4.71:1 |
| White text | 4.45:1 |
Values
| HEX | #6370CB |
| RGB | rgb(99, 112, 203) |
| HSL | hsl(233, 50%, 59%) |
| OKLCH | oklch(57.8% 0.14 275) |
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 #6370CB | 4.45:1 | AA large text | Lc -76.2 | Fine for body text |
| Black text on #6370CB | 4.71:1 | AA | Lc 33.3 | Non-text elements, placeholder text |
| #6370CB text on white | 4.45:1 | AA large text | Lc 70.8 | Content text, not long reading |
| #6370CB text on black | 4.71:1 | AA | Lc -30.9 | 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
#F4F5FB
oklch(97.1% 0.008 278.6)
-
Step 100
100
#E6E9F6
oklch(93.6% 0.018 275.6)
-
Step 200
200
#D2D8F1
oklch(88.5% 0.035 274.9)
-
Step 300
300
#B4BEEA
oklch(80.9% 0.063 274.9)
-
Step 400
400
#8E9BDF
oklch(70.6% 0.101 275.2)
-
Step 500
500
#7381D6
oklch(63% 0.129 275)
-
Step 600
600 (this color)
#6370CB
oklch(57.8% 0.14 275)
-
Step 700
700
#4D57A9
oklch(49.1% 0.13 275.3)
-
Step 800
800
#3F4889
oklch(42.8% 0.107 275)
-
Step 900
900
#353D6D
oklch(37.7% 0.082 274.6)
-
Step 950
950
#1F2440
oklch(27% 0.052 274.7)
#6370CB 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) | #497CCE | 0.039 |
| Deuteranopia (no green cones) | #3F73C9 | 0.041 |
| Tritanopia (no blue cones) | #368494 | 0.124 |
| Achromatopsia (no color) | #777777 | 0.140 |
Harmonies
Hue rotations in OKLCH that keep this color's lightness and chroma.
Complementary
The opposite hue (180°).
- #6370CB
#6370CB
oklch(57.8% 0.14 275)
- #907800
#907800
oklch(57.8% 0.119 95)
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 #6370CB, closest first.
Similar named colors
The eight closest entries in our named color list, with their ΔE distance.
- Dark Periwinkle #665FD1 ΔE 0.044
- Windows Blue #3778BF ΔE 0.054
- Slate Blue #6A5ACD ΔE 0.055
- Light Indigo #6D5ACF ΔE 0.056
- Royal Blue #4169E1 ΔE 0.057
- Iris #6258C4 ΔE 0.060
- French Blue #436BAD ΔE 0.064
- Medium Slate Blue #7B68EE ΔE 0.067
Use #6370CB 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.