#366FDD
Closest named color: Royal Blue (#4169E1). oklch(56.5% 0.179 261.9), rgb(54, 111, 221).
Aa
White text reads best on this color (4.69:1).
About this color
#366FDD is a medium-dark, vivid blue. In OKLCH its lightness is 56%, its chroma 0.179 and its hue 262°. Its hue sits on the cool side of the wheel. The nearest named color is Royal Blue (#4169E1), ΔE 0.018 away. White text reads best on it, at 4.69:1.
| Hue family | Blues |
| Lightness | medium-dark (56%) |
| Chroma | vivid (0.179) |
| Temperature | cool |
| Nearest name | Royal Blue (#4169E1) |
| Black text | 4.47:1 |
| White text | 4.69:1 |
Values
| HEX | #366FDD |
| RGB | rgb(54, 111, 221) |
| HSL | hsl(220, 71%, 54%) |
| OKLCH | oklch(56.5% 0.179 261.9) |
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 #366FDD | 4.69:1 | AA | Lc -77.6 | Fine for body text |
| Black text on #366FDD | 4.47:1 | AA large text | Lc 32.0 | Non-text elements, placeholder text |
| #366FDD text on white | 4.69:1 | AA | Lc 72.1 | Content text, not long reading |
| #366FDD text on black | 4.47:1 | AA large text | Lc -29.6 | 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
#A4C1F5
oklch(80.8% 0.081 261.9)
-
Step 400
400
#73A0F1
oklch(70.8% 0.129 261.5)
-
Step 500
500
#4F85EC
oklch(63% 0.165 262)
-
Step 600
600 (this color)
#366FDD
oklch(56.5% 0.179 261.9)
-
Step 700
700
#265ABD
oklch(49.1% 0.166 261.7)
-
Step 800
800
#214A99
oklch(42.7% 0.138 261.8)
-
Step 900
900
#203F7A
oklch(37.8% 0.107 261.8)
-
Step 950
950
#132547
oklch(26.9% 0.068 261.9)
#366FDD 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) | #2C7CE1 | 0.033 |
| Deuteranopia (no green cones) | #006DDB | 0.026 |
| Tritanopia (no blue cones) | #00899B | 0.140 |
| Achromatopsia (no color) | #747474 | 0.179 |
Harmonies
Hue rotations in OKLCH that keep this color's lightness and chroma.
Complementary
The opposite hue (180°).
- #366FDD
#366FDD
oklch(56.5% 0.179 261.9)
- #986E00
#986E00
oklch(56.6% 0.117 82)
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 #366FDD, closest first.
Similar named colors
The eight closest entries in our named color list, with their ΔE distance.
- Royal Blue #4169E1 ΔE 0.018
- Cerulean Blue #056EEE ΔE 0.033
- Neon Blue #4361EE ΔE 0.044
- Clear Blue #247AFD ΔE 0.053
- Azul #1D5DEC ΔE 0.055
- Windows Blue #3778BF ΔE 0.056
- Warm Blue #4B57DB ΔE 0.057
- Bright Blue #0165FC ΔE 0.060
Use #366FDD 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.