#3F555A
Closest named color: Dark Slate Gray (#2F4F4F). oklch(43.3% 0.028 213.2), rgb(63, 85, 90).
Aa
White text reads best on this color (7.89:1).
About this color
#3F555A is a dark close to neutral grey. In OKLCH its lightness is 43%, its chroma 0.028. It has too little chroma to lean warm or cool. The nearest named color is Dark Slate Gray (#2F4F4F), ΔE 0.033 away. White text reads best on it, at 7.89:1.
| Hue family | Neutrals |
| Lightness | dark (43%) |
| Chroma | close to neutral grey (0.028) |
| Temperature | neutral |
| Nearest name | Dark Slate Gray (#2F4F4F) |
| Black text | 2.65:1 |
| White text | 7.89:1 |
Values
| HEX | #3F555A |
| RGB | rgb(63, 85, 90) |
| HSL | hsl(191, 18%, 30%) |
| OKLCH | oklch(43.3% 0.028 213.2) |
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 #3F555A | 7.89:1 | AAA | Lc -92.1 | Preferred for body text |
| Black text on #3F555A | 2.65:1 | Fails | Lc 16.6 | Dividers and decoration only |
| #3F555A text on white | 7.89:1 | AAA | Lc 87.4 | Fine for body text |
| #3F555A text on black | 2.65:1 | Fails | Lc -14.7 | 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
#F4F6F6
oklch(97.2% 0.002 197.1)
-
Step 100
100
#E6EBEC
oklch(93.7% 0.006 211)
-
Step 200
200
#D3DBDD
oklch(88.6% 0.009 214.3)
-
Step 300
300
#B5C4C7
oklch(81% 0.017 211)
-
Step 400
400
#8FA5AA
oklch(70.7% 0.026 213)
-
Step 500
500
#738F96
oklch(63.1% 0.033 214.6)
-
Step 600
600
#5B7980
oklch(55.5% 0.036 213.6)
-
Step 700
700
#4A666C
oklch(49% 0.034 212.3)
-
Step 800
800 (this color)
#3F555A
oklch(43.3% 0.028 213.2)
-
Step 900
900
#344549
oklch(37.7% 0.023 213.7)
-
Step 950
950
#1F282A
oklch(26.9% 0.013 212.7)
#3F555A 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) | #51535A | 0.026 |
| Deuteranopia (no green cones) | #4C505A | 0.023 |
| Tritanopia (no blue cones) | #365756 | 0.016 |
| Achromatopsia (no color) | #515151 | 0.028 |
Harmonies
Hue rotations in OKLCH that keep this color's lightness and chroma.
Complementary
The opposite hue (180°).
- #3F555A
#3F555A
oklch(43.3% 0.028 213.2)
- #5F4B47
#5F4B47
oklch(43.2% 0.028 31.3)
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 #3F555A, closest first.
Similar named colors
The eight closest entries in our named color list, with their ΔE distance.
- Dark Slate Gray #2F4F4F ΔE 0.033
- YInMn Blue #415A77 ΔE 0.047
- Deep Teal #00555A ΔE 0.049
- Petrol #005F6A ΔE 0.050
- Dark Green Blue #1F6357 ΔE 0.054
- Dusty Grape #545775 ΔE 0.056
- Dark Grey Blue #29465B ΔE 0.060
- Charcoal #264653 ΔE 0.061
Use #3F555A 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.