#366DDD
Closest named color: Royal Blue (#4169E1). oklch(56% 0.181 262.5), rgb(54, 109, 221).
Aa
White text reads best on this color (4.78:1).
About this color
#366DDD is a medium-dark, vivid blue. In OKLCH its lightness is 56%, its chroma 0.181 and its hue 262°. Its hue sits on the cool side of the wheel. The nearest named color is Royal Blue (#4169E1), ΔE 0.014 away. White text reads best on it, at 4.78:1.
| Hue family | Blues |
| Lightness | medium-dark (56%) |
| Chroma | vivid (0.181) |
| Temperature | cool |
| Nearest name | Royal Blue (#4169E1) |
| Black text | 4.38:1 |
| White text | 4.78:1 |
Values
| HEX | #366DDD |
| RGB | rgb(54, 109, 221) |
| HSL | hsl(220, 71%, 54%) |
| OKLCH | oklch(56% 0.181 262.5) |
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 #366DDD | 4.78:1 | AA | Lc -78.2 | Fine for body text |
| Black text on #366DDD | 4.38:1 | AA large text | Lc 31.3 | Non-text elements, placeholder text |
| #366DDD text on white | 4.78:1 | AA | Lc 72.7 | Content text, not long reading |
| #366DDD text on black | 4.38:1 | AA large text | Lc -28.9 | 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
#F1F6FD
oklch(97.1% 0.011 256.7)
-
Step 100
100
#E1EAFA
oklch(93.5% 0.024 262.1)
-
Step 200
200
#C9DAF8
oklch(88.5% 0.045 261.9)
-
Step 300
300
#A4C1F6
oklch(80.8% 0.082 262.3)
-
Step 400
400
#749FF2
oklch(70.7% 0.131 262.7)
-
Step 500
500
#5085ED
oklch(63.2% 0.166 262.3)
-
Step 600
600 (this color)
#366DDD
oklch(56% 0.181 262.5)
-
Step 700
700
#2859BE
oklch(49.1% 0.168 262.5)
-
Step 800
800
#22499A
oklch(42.6% 0.14 262.7)
-
Step 900
900
#203E7A
oklch(37.6% 0.108 262.4)
-
Step 950
950
#132548
oklch(27% 0.069 262.3)
#366DDD 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) | #257AE1 | 0.033 |
| Deuteranopia (no green cones) | #006BDB | 0.027 |
| Tritanopia (no blue cones) | #00889B | 0.142 |
| Achromatopsia (no color) | #727272 | 0.181 |
Harmonies
Hue rotations in OKLCH that keep this color's lightness and chroma.
Complementary
The opposite hue (180°).
- #366DDD
#366DDD
oklch(56% 0.181 262.5)
- #966D00
#966D00
oklch(56.1% 0.116 82.4)
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 #366DDD, closest first.
Similar named colors
The eight closest entries in our named color list, with their ΔE distance.
- Royal Blue #4169E1 ΔE 0.014
- Cerulean Blue #056EEE ΔE 0.033
- Neon Blue #4361EE ΔE 0.040
- Azul #1D5DEC ΔE 0.051
- Warm Blue #4B57DB ΔE 0.053
- Clear Blue #247AFD ΔE 0.055
- Bright Blue #0165FC ΔE 0.057
- Windows Blue #3778BF ΔE 0.059
Use #366DDD 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.