#366FDB
Closest named color: Royal Blue (#4169E1). oklch(56.3% 0.176 261.7), rgb(54, 111, 219).
Aa
White text reads best on this color (4.71:1).
About this color
#366FDB is a medium-dark, vivid blue. In OKLCH its lightness is 56%, its chroma 0.176 and its hue 262°. Its hue sits on the cool side of the wheel. The nearest named color is Royal Blue (#4169E1), ΔE 0.020 away. White text reads best on it, at 4.71:1.
| Hue family | Blues |
| Lightness | medium-dark (56%) |
| Chroma | vivid (0.176) |
| Temperature | cool |
| Nearest name | Royal Blue (#4169E1) |
| Black text | 4.45:1 |
| White text | 4.71:1 |
Values
| HEX | #366FDB |
| RGB | rgb(54, 111, 219) |
| HSL | hsl(219, 70%, 54%) |
| OKLCH | oklch(56.3% 0.176 261.7) |
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 #366FDB | 4.71:1 | AA | Lc -77.7 | Fine for body text |
| Black text on #366FDB | 4.45:1 | AA large text | Lc 31.8 | Non-text elements, placeholder text |
| #366FDB text on white | 4.71:1 | AA | Lc 72.3 | Content text, not long reading |
| #366FDB 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
#F2F6FD
oklch(97.2% 0.01 261.8)
-
Step 100
100
#E2EAFA
oklch(93.6% 0.023 264.5)
-
Step 200
200
#C9DAF7
oklch(88.5% 0.044 261.2)
-
Step 300
300
#A5C1F5
oklch(80.9% 0.08 262.6)
-
Step 400
400
#74A0EF
oklch(70.7% 0.126 261.5)
-
Step 500
500
#5086EA
oklch(63.2% 0.161 261.6)
-
Step 600
600 (this color)
#366FDB
oklch(56.3% 0.176 261.7)
-
Step 700
700
#275ABC
oklch(49.1% 0.164 261.8)
-
Step 800
800
#214A98
oklch(42.7% 0.136 261.7)
-
Step 900
900
#203F79
oklch(37.8% 0.106 261.6)
-
Step 950
950
#132547
oklch(26.9% 0.068 261.9)
#366FDB 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) | #2E7BDF | 0.031 |
| Deuteranopia (no green cones) | #006CD9 | 0.028 |
| Tritanopia (no blue cones) | #00899A | 0.139 |
| Achromatopsia (no color) | #737373 | 0.176 |
Harmonies
Hue rotations in OKLCH that keep this color's lightness and chroma.
Complementary
The opposite hue (180°).
- #366FDB
#366FDB
oklch(56.3% 0.176 261.7)
- #976D00
#976D00
oklch(56.3% 0.116 81.8)
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 #366FDB, closest first.
Similar named colors
The eight closest entries in our named color list, with their ΔE distance.
- Royal Blue #4169E1 ΔE 0.020
- Cerulean Blue #056EEE ΔE 0.036
- Neon Blue #4361EE ΔE 0.046
- Windows Blue #3778BF ΔE 0.053
- Clear Blue #247AFD ΔE 0.056
- Azul #1D5DEC ΔE 0.057
- Warm Blue #4B57DB ΔE 0.058
- Bright Blue #0165FC ΔE 0.062
Use #366FDB 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.