#0666C3
Closest named color: Mid Blue (#276AB3). oklch(51.6% 0.165 254.7), rgb(6, 102, 195).
Aa
White text reads best on this color (5.68:1).
About this color
#0666C3 is a medium-dark, vivid blue. In OKLCH its lightness is 52%, its chroma 0.165 and its hue 255°. Its hue sits on the cool side of the wheel. The nearest named color is Mid Blue (#276AB3), ΔE 0.032 away. White text reads best on it, at 5.68:1.
| Hue family | Blues |
| Lightness | medium-dark (52%) |
| Chroma | vivid (0.165) |
| Temperature | cool |
| Nearest name | Mid Blue (#276AB3) |
| Black text | 3.69:1 |
| White text | 5.68:1 |
Values
| HEX | #0666C3 |
| RGB | rgb(6, 102, 195) |
| HSL | hsl(210, 94%, 39%) |
| OKLCH | oklch(51.6% 0.165 254.7) |
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 #0666C3 | 5.68:1 | AA | Lc -83.0 | Fine for body text |
| Black text on #0666C3 | 3.69:1 | AA large text | Lc 26.4 | Dividers and decoration only |
| #0666C3 text on white | 5.68:1 | AA | Lc 77.7 | Fine for body text |
| #0666C3 text on black | 3.69:1 | AA large text | Lc -24.1 | 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 700.
-
Step 50
50
#F1F6FD
oklch(97.1% 0.011 256.7)
-
Step 100
100
#E0EBFA
oklch(93.6% 0.024 256.1)
-
Step 200
200
#C6DBF7
oklch(88.5% 0.045 255.6)
-
Step 300
300
#9EC4F4
oklch(81% 0.08 254.5)
-
Step 400
400
#67A3EE
oklch(70.6% 0.127 254.7)
-
Step 500
500
#398AE9
oklch(63.1% 0.163 254.6)
-
Step 600
600
#0871D7
oklch(55.5% 0.177 254.7)
-
Step 700
700 (this color)
#0666C3
oklch(51.6% 0.165 254.7)
-
Step 800
800
#034E97
oklch(42.8% 0.136 254.4)
-
Step 900
900
#114178
oklch(37.6% 0.106 254.9)
-
Step 950
950
#0C2746
oklch(27.1% 0.066 254)
#0666C3 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) | #2F6FC6 | 0.034 |
| Deuteranopia (no green cones) | #0060C1 | 0.017 |
| Tritanopia (no blue cones) | #007D8B | 0.123 |
| Achromatopsia (no color) | #676767 | 0.165 |
Harmonies
Hue rotations in OKLCH that keep this color's lightness and chroma.
Complementary
The opposite hue (180°).
- #0666C3
#0666C3
oklch(51.6% 0.165 254.7)
- #8C5D00
#8C5D00
oklch(51.6% 0.109 74.8)
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 #0666C3, closest first.
Similar named colors
The eight closest entries in our named color list, with their ΔE distance.
- Mid Blue #276AB3 ΔE 0.032
- French Blue #436BAD ΔE 0.055
- Windows Blue #3778BF ΔE 0.061
- Royal Blue #4169E1 ΔE 0.061
- Cerulean Blue #056EEE ΔE 0.068
- Azul #1D5DEC ΔE 0.068
- Nice Blue #107AB0 ΔE 0.069
- Warm Blue #4B57DB ΔE 0.069
Use #0666C3 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.