#366DE3
Closest named color: Royal Blue (#4169E1). oklch(56.5% 0.189 263), rgb(54, 109, 227).
Aa
White text reads best on this color (4.71:1).
About this color
#366DE3 is a medium-dark, vivid blue. In OKLCH its lightness is 56%, its chroma 0.189 and its hue 263°. Its hue sits on the cool side of the wheel. The nearest named color is Royal Blue (#4169E1), ΔE 0.012 away. White text reads best on it, at 4.71:1.
| Hue family | Blues |
| Lightness | medium-dark (56%) |
| Chroma | vivid (0.189) |
| Temperature | cool |
| Nearest name | Royal Blue (#4169E1) |
| Black text | 4.45:1 |
| White text | 4.71:1 |
Values
| HEX | #366DE3 |
| RGB | rgb(54, 109, 227) |
| HSL | hsl(221, 76%, 55%) |
| OKLCH | oklch(56.5% 0.189 263) |
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 #366DE3 | 4.71:1 | AA | Lc -77.7 | Fine for body text |
| Black text on #366DE3 | 4.45:1 | AA large text | Lc 31.8 | Non-text elements, placeholder text |
| #366DE3 text on white | 4.71:1 | AA | Lc 72.2 | Content text, not long reading |
| #366DE3 text on black | 4.45:1 | AA large text | Lc -29.4 | 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
#E1EAFB
oklch(93.5% 0.025 263.3)
-
Step 200
200
#C9DAF9
oklch(88.5% 0.047 262.5)
-
Step 300
300
#A4C1F8
oklch(80.9% 0.084 263)
-
Step 400
400
#739FF5
oklch(70.8% 0.135 262.8)
-
Step 500
500
#4F84F1
oklch(63.2% 0.173 262.9)
-
Step 600
600 (this color)
#366DE3
oklch(56.5% 0.189 263)
-
Step 700
700
#2758C2
oklch(49.1% 0.175 262.9)
-
Step 800
800
#21489D
oklch(42.6% 0.146 263.1)
-
Step 900
900
#1F3E7D
oklch(37.8% 0.113 262.6)
-
Step 950
950
#132549
oklch(27.1% 0.071 262.6)
#366DE3 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) | #187CE7 | 0.038 |
| Deuteranopia (no green cones) | #006CE1 | 0.025 |
| Tritanopia (no blue cones) | #008A9D | 0.150 |
| Achromatopsia (no color) | #737373 | 0.189 |
Harmonies
Hue rotations in OKLCH that keep this color's lightness and chroma.
Complementary
The opposite hue (180°).
- #366DE3
#366DE3
oklch(56.5% 0.189 263)
- #976E00
#976E00
oklch(56.5% 0.116 82.6)
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 #366DE3, closest first.
Similar named colors
The eight closest entries in our named color list, with their ΔE distance.
- Royal Blue #4169E1 ΔE 0.012
- Cerulean Blue #056EEE ΔE 0.026
- Neon Blue #4361EE ΔE 0.034
- Azul #1D5DEC ΔE 0.047
- Clear Blue #247AFD ΔE 0.048
- Bright Blue #0165FC ΔE 0.050
- Warm Blue #4B57DB ΔE 0.053
- Dark Periwinkle #665FD1 ΔE 0.064
Use #366DE3 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.