#646BB3
Closest named color: French Blue (#436BAD). oklch(55.4% 0.111 277.9), rgb(100, 107, 179).
Aa
White text reads best on this color (4.88:1).
About this color
#646BB3 is a medium-dark, moderately saturated blue. In OKLCH its lightness is 55%, its chroma 0.111 and its hue 278°. Its hue sits on the cool side of the wheel. The nearest named color is French Blue (#436BAD), ΔE 0.043 away. White text reads best on it, at 4.88:1.
| Hue family | Blues |
| Lightness | medium-dark (55%) |
| Chroma | moderately saturated (0.111) |
| Temperature | cool |
| Nearest name | French Blue (#436BAD) |
| Black text | 4.29:1 |
| White text | 4.88:1 |
Values
| HEX | #646BB3 |
| RGB | rgb(100, 107, 179) |
| HSL | hsl(235, 34%, 55%) |
| OKLCH | oklch(55.4% 0.111 277.9) |
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 #646BB3 | 4.88:1 | AA | Lc -79.2 | Fine for body text |
| Black text on #646BB3 | 4.29:1 | AA large text | Lc 30.3 | Non-text elements, placeholder text |
| #646BB3 text on white | 4.88:1 | AA | Lc 73.8 | Content text, not long reading |
| #646BB3 text on black | 4.29:1 | AA large text | Lc -27.9 | 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
#E7E9F4
oklch(93.6% 0.015 277.8)
-
Step 200
200
#D4D8EC
oklch(88.5% 0.028 276.8)
-
Step 300
300
#B8BEE1
oklch(80.8% 0.05 277.6)
-
Step 400
400
#949CD3
oklch(70.7% 0.081 277.7)
-
Step 500
500
#7B83C7
oklch(63.1% 0.102 277.9)
-
Step 600
600 (this color)
#646BB3
oklch(55.4% 0.111 277.9)
-
Step 700
700
#53599A
oklch(49% 0.104 277.8)
-
Step 800
800
#44497D
oklch(42.6% 0.086 277.9)
-
Step 900
900
#393E65
oklch(37.8% 0.067 277.1)
-
Step 950
950
#21243B
oklch(26.9% 0.043 277.4)
#646BB3 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) | #5174B6 | 0.031 |
| Deuteranopia (no green cones) | #4B6EB1 | 0.032 |
| Tritanopia (no blue cones) | #4A7A86 | 0.099 |
| Achromatopsia (no color) | #717171 | 0.112 |
Harmonies
Hue rotations in OKLCH that keep this color's lightness and chroma.
Complementary
The opposite hue (180°).
- #646BB3
#646BB3
oklch(55.4% 0.111 277.9)
- #85730B
#85730B
oklch(55.6% 0.112 97.9)
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 #646BB3, closest first.
No curated palette has a color within ΔE 0.04 of #646BB3.
Similar named colors
The eight closest entries in our named color list, with their ΔE distance.
- French Blue #436BAD ΔE 0.043
- Flat Blue #3C73A8 ΔE 0.055
- Windows Blue #3778BF ΔE 0.056
- Iris #6258C4 ΔE 0.060
- Dark Periwinkle #665FD1 ΔE 0.060
- Dull Blue #49759C ΔE 0.061
- Muted Blue #3B719F ΔE 0.062
- Slate Blue #6A5ACD ΔE 0.063
Use #646BB3 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.