#366EE4
Closest named color: Royal Blue (#4169E1). oklch(56.8% 0.189 262.8), rgb(54, 110, 228).
Aa
White text reads best on this color (4.65:1).
About this color
#366EE4 is a medium-dark, vivid blue. In OKLCH its lightness is 57%, 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 0.014 away. White text reads best on it, at 4.65:1.
| Hue family | Blues |
| Lightness | medium-dark (57%) |
| Chroma | vivid (0.189) |
| Temperature | cool |
| Nearest name | Royal Blue (#4169E1) |
| Black text | 4.50:1 |
| White text | 4.65:1 |
Values
| HEX | #366EE4 |
| RGB | rgb(54, 110, 228) |
| HSL | hsl(221, 76%, 55%) |
| OKLCH | oklch(56.8% 0.189 262.8) |
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 #366EE4 | 4.65:1 | AA | Lc -77.3 | Fine for body text |
| Black text on #366EE4 | 4.50:1 | AA | Lc 32.2 | Non-text elements, placeholder text |
| #366EE4 text on white | 4.65:1 | AA | Lc 71.9 | Content text, not long reading |
| #366EE4 text on black | 4.50:1 | AA | Lc -29.8 | 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
#729FF5
oklch(70.7% 0.136 262.5)
-
Step 500
500
#4E84F1
oklch(63.1% 0.174 262.7)
-
Step 600
600 (this color)
#366EE4
oklch(56.8% 0.189 262.8)
-
Step 700
700
#2658C3
oklch(49.2% 0.176 262.8)
-
Step 800
800
#20489D
oklch(42.6% 0.146 262.8)
-
Step 900
900
#1F3E7D
oklch(37.8% 0.113 262.6)
-
Step 950
950
#132549
oklch(27.1% 0.071 262.6)
#366EE4 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) | #1B7DE8 | 0.038 |
| Deuteranopia (no green cones) | #006DE2 | 0.025 |
| Tritanopia (no blue cones) | #008B9E | 0.150 |
| Achromatopsia (no color) | #747474 | 0.189 |
Harmonies
Hue rotations in OKLCH that keep this color's lightness and chroma.
Complementary
The opposite hue (180°).
- #366EE4
#366EE4
oklch(56.8% 0.189 262.8)
- #986F00
#986F00
oklch(56.8% 0.117 82.9)
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 #366EE4, 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 0.026
- Neon Blue #4361EE ΔE 0.035
- Clear Blue #247AFD ΔE 0.045
- Azul #1D5DEC ΔE 0.049
- Bright Blue #0165FC ΔE 0.050
- Warm Blue #4B57DB ΔE 0.055
- Dark Periwinkle #665FD1 ΔE 0.065
Use #366EE4 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.