#646CB6
Closest named color: French Blue (#436BAD). oklch(55.8% 0.114 277.3), rgb(100, 108, 182).
Aa
White text reads best on this color (4.81:1).
About this color
#646CB6 is a medium-dark, moderately saturated blue. In OKLCH its lightness is 56%, its chroma 0.114 and its hue 277°. Its hue sits on the cool side of the wheel. The nearest named color is French Blue (#436BAD), ΔE 0.045 away. White text reads best on it, at 4.81:1.
| Hue family | Blues |
| Lightness | medium-dark (56%) |
| Chroma | moderately saturated (0.114) |
| Temperature | cool |
| Nearest name | French Blue (#436BAD) |
| Black text | 4.36:1 |
| White text | 4.81:1 |
Values
| HEX | #646CB6 |
| RGB | rgb(100, 108, 182) |
| HSL | hsl(234, 36%, 55%) |
| OKLCH | oklch(55.8% 0.114 277.3) |
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 #646CB6 | 4.81:1 | AA | Lc -78.7 | Fine for body text |
| Black text on #646CB6 | 4.36:1 | AA large text | Lc 30.8 | Non-text elements, placeholder text |
| #646CB6 text on white | 4.81:1 | AA | Lc 73.3 | Content text, not long reading |
| #646CB6 text on black | 4.36:1 | AA large text | Lc -28.4 | 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
#E7E9F4
oklch(93.6% 0.015 277.8)
-
Step 200
200
#D4D8EC
oklch(88.5% 0.028 276.8)
-
Step 300
300
#B8BEE2
oklch(80.9% 0.051 277.7)
-
Step 400
400
#949CD4
oklch(70.7% 0.082 277.8)
-
Step 500
500
#7A83C9
oklch(63.2% 0.106 277.3)
-
Step 600
600 (this color)
#646CB6
oklch(55.8% 0.114 277.3)
-
Step 700
700
#52599C
oklch(49% 0.107 277.2)
-
Step 800
800
#43497F
oklch(42.6% 0.089 277.1)
-
Step 900
900
#393E66
oklch(37.9% 0.068 277.2)
-
Step 950
950
#21243C
oklch(27% 0.045 277.5)
#646CB6 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) | #5175B9 | 0.031 |
| Deuteranopia (no green cones) | #4A6FB4 | 0.033 |
| Tritanopia (no blue cones) | #487B88 | 0.101 |
| Achromatopsia (no color) | #727272 | 0.115 |
Harmonies
Hue rotations in OKLCH that keep this color's lightness and chroma.
Complementary
The opposite hue (180°).
- #646CB6
#646CB6
oklch(55.8% 0.114 277.3)
- #877303
#877303
oklch(55.8% 0.114 96.9)
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 #646CB6, closest first.
No curated palette has a color within ΔE 0.04 of #646CB6.
Similar named colors
The eight closest entries in our named color list, with their ΔE distance.
- French Blue #436BAD ΔE 0.045
- Windows Blue #3778BF ΔE 0.054
- Flat Blue #3C73A8 ΔE 0.056
- Dark Periwinkle #665FD1 ΔE 0.057
- Iris #6258C4 ΔE 0.059
- Slate Blue #6A5ACD ΔE 0.062
- Dull Blue #49759C ΔE 0.063
- Light Indigo #6D5ACF ΔE 0.064
Use #646CB6 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.