#066DE3
Closest named color: Cerulean Blue (#056EEE). oklch(55.5% 0.198 257.4), rgb(6, 109, 227).
Aa
White text reads best on this color (4.87:1).
About this color
#066DE3 is a medium-dark, vivid blue. In OKLCH its lightness is 55%, its chroma 0.198 and its hue 257°. Its hue sits on the cool side of the wheel. The nearest named color is Cerulean Blue (#056EEE), ΔE 0.017 away. White text reads best on it, at 4.87:1.
| Hue family | Blues |
| Lightness | medium-dark (55%) |
| Chroma | vivid (0.198) |
| Temperature | cool |
| Nearest name | Cerulean Blue (#056EEE) |
| Black text | 4.30:1 |
| White text | 4.87:1 |
Values
| HEX | #066DE3 |
| RGB | rgb(6, 109, 227) |
| HSL | hsl(212, 95%, 46%) |
| OKLCH | oklch(55.5% 0.198 257.4) |
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 #066DE3 | 4.87:1 | AA | Lc -78.4 | Fine for body text |
| Black text on #066DE3 | 4.30:1 | AA large text | Lc 31.1 | Non-text elements, placeholder text |
| #066DE3 text on white | 4.87:1 | AA | Lc 73.0 | Content text, not long reading |
| #066DE3 text on black | 4.30:1 | AA large text | Lc -28.7 | 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
#F1F6FE
oklch(97.2% 0.012 259.8)
-
Step 100
100
#DFEBFB
oklch(93.6% 0.025 255.6)
-
Step 200
200
#C5DBFA
oklch(88.5% 0.049 256.9)
-
Step 300
300
#9CC3FA
oklch(80.9% 0.089 257)
-
Step 400
400
#65A1F8
oklch(70.6% 0.143 257.7)
-
Step 500
500
#3787F5
oklch(63.2% 0.182 257.4)
-
Step 600
600 (this color)
#066DE3
oklch(55.5% 0.198 257.4)
-
Step 700
700
#005BC2
oklch(49% 0.177 257.5)
-
Step 800
800
#034BA0
oklch(42.8% 0.152 257.4)
-
Step 900
900
#103F7F
oklch(37.6% 0.119 257.7)
-
Step 950
950
#0B264A
oklch(27.1% 0.074 256.8)
#066DE3 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) | #0D7BE7 | 0.037 |
| Deuteranopia (no green cones) | #0068E1 | 0.013 |
| Tritanopia (no blue cones) | #008A9D | 0.149 |
| Achromatopsia (no color) | #717171 | 0.198 |
Harmonies
Hue rotations in OKLCH that keep this color's lightness and chroma.
Complementary
The opposite hue (180°).
- #066DE3
#066DE3
oklch(55.5% 0.198 257.4)
- #986900
#986900
oklch(55.6% 0.116 77.9)
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 #066DE3, closest first.
No curated palette has a color within ΔE 0.04 of #066DE3.
Similar named colors
The eight closest entries in our named color list, with their ΔE distance.
- Cerulean Blue #056EEE ΔE 0.017
- Royal Blue #4169E1 ΔE 0.032
- Azul #1D5DEC ΔE 0.040
- Bright Blue #0165FC ΔE 0.043
- Neon Blue #4361EE ΔE 0.045
- Clear Blue #247AFD ΔE 0.053
- Warm Blue #4B57DB ΔE 0.062
- Windows Blue #3778BF ΔE 0.071
Use #066DE3 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.