#366AD9
Closest named color: Royal Blue (#4169E1). oklch(55.1% 0.18 263), rgb(54, 106, 217).
Aa
White text reads best on this color (4.97:1).
About this color
#366AD9 is a medium-dark, vivid blue. In OKLCH its lightness is 55%, its chroma 0.180 and its hue 263°. Its hue sits on the cool side of the wheel. The nearest named color is Royal Blue (#4169E1), ΔE 0.016 away. White text reads best on it, at 4.97:1.
| Hue family | Blues |
| Lightness | medium-dark (55%) |
| Chroma | vivid (0.180) |
| Temperature | cool |
| Nearest name | Royal Blue (#4169E1) |
| Black text | 4.22:1 |
| White text | 4.97:1 |
Values
| HEX | #366AD9 |
| RGB | rgb(54, 106, 217) |
| HSL | hsl(221, 68%, 53%) |
| OKLCH | oklch(55.1% 0.18 263) |
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 #366AD9 | 4.97:1 | AA | Lc -79.4 | Fine for body text |
| Black text on #366AD9 | 4.22:1 | AA large text | Lc 30.1 | Non-text elements, placeholder text |
| #366AD9 text on white | 4.97:1 | AA | Lc 74.0 | Content text, not long reading |
| #366AD9 text on black | 4.22:1 | AA large text | Lc -27.7 | 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
#F2F6FD
oklch(97.2% 0.01 261.8)
-
Step 100
100
#E2EAFA
oklch(93.6% 0.023 264.5)
-
Step 200
200
#CADAF8
oklch(88.6% 0.045 263.1)
-
Step 300
300
#A5C1F6
oklch(80.9% 0.081 263)
-
Step 400
400
#759FF1
oklch(70.7% 0.129 262.9)
-
Step 500
500
#5285EC
oklch(63.2% 0.164 262.8)
-
Step 600
600 (this color)
#366AD9
oklch(55.1% 0.18 263)
-
Step 700
700
#2A59BE
oklch(49.1% 0.167 263)
-
Step 800
800
#244999
oklch(42.6% 0.138 263.1)
-
Step 900
900
#213E7A
oklch(37.6% 0.108 262.9)
-
Step 950
950
#142547
oklch(27% 0.067 262.7)
#366AD9 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) | #2178DD | 0.036 |
| Deuteranopia (no green cones) | #0069D7 | 0.026 |
| Tritanopia (no blue cones) | #008597 | 0.142 |
| Achromatopsia (no color) | #707070 | 0.180 |
Harmonies
Hue rotations in OKLCH that keep this color's lightness and chroma.
Complementary
The opposite hue (180°).
- #366AD9
#366AD9
oklch(55.1% 0.18 263)
- #926B00
#926B00
oklch(55.3% 0.114 83.3)
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 #366AD9, closest first.
Similar named colors
The eight closest entries in our named color list, with their ΔE distance.
- Royal Blue #4169E1 ΔE 0.016
- Cerulean Blue #056EEE ΔE 0.037
- Neon Blue #4361EE ΔE 0.040
- Warm Blue #4B57DB ΔE 0.047
- Azul #1D5DEC ΔE 0.049
- Dark Periwinkle #665FD1 ΔE 0.059
- Windows Blue #3778BF ΔE 0.059
- Bright Blue #0165FC ΔE 0.060
Use #366AD9 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.