#663B40
Closest named color: Purple Brown (#673A3F). oklch(40.6% 0.061 12.6), rgb(102, 59, 64).
Aa
White text reads best on this color (9.27:1).
About this color
#663B40 is a dark, muted red. In OKLCH its lightness is 41%, its chroma 0.061 and its hue 13°. Its hue sits on the warm side of the wheel. The nearest named color is Purple Brown (#673A3F), ΔE 0.003 away. White text reads best on it, at 9.27:1.
| Hue family | Reds |
| Lightness | dark (41%) |
| Chroma | muted (0.061) |
| Temperature | warm |
| Nearest name | Purple Brown (#673A3F) |
| Black text | 2.26:1 |
| White text | 9.27:1 |
Values
| HEX | #663B40 |
| RGB | rgb(102, 59, 64) |
| HSL | hsl(353, 27%, 32%) |
| OKLCH | oklch(40.6% 0.061 12.6) |
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 #663B40 | 9.27:1 | AAA | Lc -95.6 | Preferred for body text |
| Black text on #663B40 | 2.26:1 | Fails | Lc 12.7 | Not readable |
| #663B40 text on white | 9.27:1 | AAA | Lc 91.2 | Preferred for body text |
| #663B40 text on black | 2.26:1 | Fails | Lc -11.1 | Not readable |
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 800.
-
Step 50
50
#F9F4F4
oklch(97.1% 0.005 17.2)
-
Step 100
100
#F1E7E8
oklch(93.6% 0.011 10.3)
-
Step 200
200
#E6D4D5
oklch(88.5% 0.02 13.7)
-
Step 300
300
#D7B8BA
oklch(81% 0.036 13.5)
-
Step 400
400
#C19297
oklch(70.6% 0.057 11.5)
-
Step 500
500
#B1777D
oklch(63.1% 0.073 12.6)
-
Step 600
600
#9C5F66
oklch(55.5% 0.08 12.6)
-
Step 700
700
#854F55
oklch(49.2% 0.073 12.9)
-
Step 800
800 (this color)
#663B40
oklch(40.6% 0.061 12.6)
-
Step 900
900
#58373A
oklch(37.7% 0.047 13.6)
-
Step 950
950
#342022
oklch(27% 0.031 12.8)
#663B40 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) | #434240 | 0.066 |
| Deuteranopia (no green cones) | #4D4A3F | 0.061 |
| Tritanopia (no blue cones) | #6D373D | 0.016 |
| Achromatopsia (no color) | #474747 | 0.062 |
Harmonies
Hue rotations in OKLCH that keep this color's lightness and chroma.
Complementary
The opposite hue (180°).
- #663B40
#663B40
oklch(40.6% 0.061 12.6)
- #165452
#165452
oklch(40.7% 0.061 191.9)
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 #663B40, closest first.
Similar named colors
The eight closest entries in our named color list, with their ΔE distance.
- Purple Brown #673A3F ΔE 0.003
- Brownish Purple #76424E ΔE 0.042
- Chestnut #742802 ΔE 0.072
- Charcoal Grey #3C4142 ΔE 0.076
- Mud Brown #60460F ΔE 0.079
- Red Brown #8B2E16 ΔE 0.084
- Rust Brown #8B3103 ΔE 0.090
- Dark Mauve #874C62 ΔE 0.092
Use #663B40 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.