#665BCB
Closest named color: Slate Blue (#6A5ACD). oklch(54.1% 0.168 283.7), rgb(102, 91, 203).
Aa
White text reads best on this color (5.35:1).
About this color
#665BCB is a medium-dark, vivid purple. In OKLCH its lightness is 54%, its chroma 0.168 and its hue 284°. Its hue sits on the cool side of the wheel. The nearest named color is Slate Blue (#6A5ACD), ΔE 0.007 away. White text reads best on it, at 5.35:1.
| Hue family | Purples |
| Lightness | medium-dark (54%) |
| Chroma | vivid (0.168) |
| Temperature | cool |
| Nearest name | Slate Blue (#6A5ACD) |
| Black text | 3.92:1 |
| White text | 5.35:1 |
Values
| HEX | #665BCB |
| RGB | rgb(102, 91, 203) |
| HSL | hsl(246, 52%, 58%) |
| OKLCH | oklch(54.1% 0.168 283.7) |
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 #665BCB | 5.35:1 | AA | Lc -81.7 | Fine for body text |
| Black text on #665BCB | 3.92:1 | AA large text | Lc 27.7 | Dividers and decoration only |
| #665BCB text on white | 5.35:1 | AA | Lc 76.4 | Fine for body text |
| #665BCB text on black | 3.92:1 | AA large text | Lc -25.4 | 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
#F4F5FC
oklch(97.1% 0.009 279.7)
-
Step 100
100
#E7E8F8
oklch(93.5% 0.022 283.1)
-
Step 200
200
#D5D6F5
oklch(88.5% 0.042 284)
-
Step 300
300
#BABBF0
oklch(81% 0.074 283.8)
-
Step 400
400
#9796E9
oklch(70.7% 0.12 283.4)
-
Step 500
500
#7F79E2
oklch(63% 0.154 283.6)
-
Step 600
600 (this color)
#665BCB
oklch(54.1% 0.168 283.7)
-
Step 700
700
#594EB4
oklch(49% 0.156 283.9)
-
Step 800
800
#484192
oklch(42.7% 0.129 283.4)
-
Step 900
900
#3C3874
oklch(37.7% 0.1 283.5)
-
Step 950
950
#232144
oklch(27% 0.064 283.9)
#665BCB 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) | #166ECF | 0.083 |
| Deuteranopia (no green cones) | #0967C9 | 0.084 |
| Tritanopia (no blue cones) | #40748A | 0.142 |
| Achromatopsia (no color) | #6B6B6B | 0.168 |
Harmonies
Hue rotations in OKLCH that keep this color's lightness and chroma.
Complementary
The opposite hue (180°).
- #665BCB
#665BCB
oklch(54.1% 0.168 283.7)
- #7B7100
#7B7100
oklch(54.1% 0.114 103.4)
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 #665BCB, closest first.
Similar named colors
The eight closest entries in our named color list, with their ΔE distance.
- Slate Blue #6A5ACD ΔE 0.007
- Light Indigo #6D5ACF ΔE 0.013
- Dark Periwinkle #665FD1 ΔE 0.013
- Iris #6258C4 ΔE 0.014
- Warm Blue #4B57DB ΔE 0.048
- Bluey Purple #6241C7 ΔE 0.058
- Royal Blue #4169E1 ΔE 0.060
- Purpley #8756E4 ΔE 0.066
Use #665BCB 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.