#1B66DF
Closest named color: Cerulean Blue (#056EEE). oklch(54% 0.198 260.2), rgb(27, 102, 223).
Aa
White text reads best on this color (5.23:1).
About this color
#1B66DF is a medium-dark, vivid blue. In OKLCH its lightness is 54%, its chroma 0.198 and its hue 260°. Its hue sits on the cool side of the wheel. The nearest named color is Cerulean Blue (#056EEE), ΔE 0.029 away. White text reads best on it, at 5.23:1.
| Hue family | Blues |
| Lightness | medium-dark (54%) |
| Chroma | vivid (0.198) |
| Temperature | cool |
| Nearest name | Cerulean Blue (#056EEE) |
| Black text | 4.01:1 |
| White text | 5.23:1 |
Values
| HEX | #1B66DF |
| RGB | rgb(27, 102, 223) |
| HSL | hsl(217, 78%, 49%) |
| OKLCH | oklch(54% 0.198 260.2) |
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 #1B66DF | 5.23:1 | AA | Lc -80.6 | Fine for body text |
| Black text on #1B66DF | 4.01:1 | AA large text | Lc 28.8 | Dividers and decoration only |
| #1B66DF text on white | 5.23:1 | AA | Lc 75.3 | Fine for body text |
| #1B66DF text on black | 4.01:1 | AA large text | Lc -26.5 | 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
#E0EBFC
oklch(93.7% 0.026 259)
-
Step 200
200
#C7DAFB
oklch(88.5% 0.05 261.5)
-
Step 300
300
#9FC2FB
oklch(80.9% 0.09 260)
-
Step 400
400
#6BA0F9
oklch(70.8% 0.143 260.3)
-
Step 500
500
#4285F6
oklch(63.2% 0.183 260.2)
-
Step 600
600 (this color)
#1B66DF
oklch(54% 0.198 260.2)
-
Step 700
700
#1358C7
oklch(49% 0.185 260.3)
-
Step 800
800
#1349A1
oklch(42.7% 0.153 260.2)
-
Step 900
900
#173E7F
oklch(37.6% 0.119 260.1)
-
Step 950
950
#0F254B
oklch(27% 0.076 260.5)
#1B66DF 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) | #0075E3 | 0.037 |
| Deuteranopia (no green cones) | #0064DD | 0.011 |
| Tritanopia (no blue cones) | #008498 | 0.151 |
| Achromatopsia (no color) | #6C6C6C | 0.198 |
Harmonies
Hue rotations in OKLCH that keep this color's lightness and chroma.
Complementary
The opposite hue (180°).
- #1B66DF
#1B66DF
oklch(54% 0.198 260.2)
- #906600
#906600
oklch(54% 0.112 80.3)
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 #1B66DF, closest first.
Similar named colors
The eight closest entries in our named color list, with their ΔE distance.
- Cerulean Blue #056EEE ΔE 0.029
- Azul #1D5DEC ΔE 0.029
- Royal Blue #4169E1 ΔE 0.031
- Neon Blue #4361EE ΔE 0.039
- Bright Blue #0165FC ΔE 0.044
- Warm Blue #4B57DB ΔE 0.048
- Electric Blue #0652FF ΔE 0.066
- Clear Blue #247AFD ΔE 0.067
Use #1B66DF 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.