#366FD0
Closest named color: Royal Blue (#4169E1). oklch(55.5% 0.162 260.3), rgb(54, 111, 208).
Aa
White text reads best on this color (4.83:1).
About this color
#366FD0 is a medium-dark, vivid blue. In OKLCH its lightness is 56%, its chroma 0.162 and its hue 260°. Its hue sits on the cool side of the wheel. The nearest named color is Royal Blue (#4169E1), ΔE 0.033 away. White text reads best on it, at 4.83:1.
| Hue family | Blues |
| Lightness | medium-dark (56%) |
| Chroma | vivid (0.162) |
| Temperature | cool |
| Nearest name | Royal Blue (#4169E1) |
| Black text | 4.34:1 |
| White text | 4.83:1 |
Values
| HEX | #366FD0 |
| RGB | rgb(54, 111, 208) |
| HSL | hsl(218, 62%, 51%) |
| OKLCH | oklch(55.5% 0.162 260.3) |
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 #366FD0 | 4.83:1 | AA | Lc -78.6 | Fine for body text |
| Black text on #366FD0 | 4.34:1 | AA large text | Lc 30.9 | Non-text elements, placeholder text |
| #366FD0 text on white | 4.83:1 | AA | Lc 73.1 | Content text, not long reading |
| #366FD0 text on black | 4.34:1 | AA large text | Lc -28.5 | 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
#F2F6FC
oklch(97.2% 0.009 258.3)
-
Step 100
100
#E2EAF8
oklch(93.5% 0.021 261.8)
-
Step 200
200
#CADAF5
oklch(88.5% 0.041 260.9)
-
Step 300
300
#A6C2F0
oklch(80.9% 0.072 260.3)
-
Step 400
400
#76A1E9
oklch(70.8% 0.116 260.3)
-
Step 500
500
#5287E2
oklch(63% 0.149 260.5)
-
Step 600
600 (this color)
#366FD0
oklch(55.5% 0.162 260.3)
-
Step 700
700
#295CB4
oklch(49% 0.15 260.5)
-
Step 800
800
#234C92
oklch(42.7% 0.124 260.4)
-
Step 900
900
#214074
oklch(37.7% 0.097 260.1)
-
Step 950
950
#142644
oklch(27% 0.061 260.1)
#366FD0 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) | #3B79D4 | 0.028 |
| Deuteranopia (no green cones) | #136BCE | 0.025 |
| Tritanopia (no blue cones) | #008695 | 0.128 |
| Achromatopsia (no color) | #727272 | 0.162 |
Harmonies
Hue rotations in OKLCH that keep this color's lightness and chroma.
Complementary
The opposite hue (180°).
- #366FD0
#366FD0
oklch(55.5% 0.162 260.3)
- #966A00
#966A00
oklch(55.5% 0.115 79.9)
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 #366FD0, closest first.
Similar named colors
The eight closest entries in our named color list, with their ΔE distance.
- Royal Blue #4169E1 ΔE 0.033
- Windows Blue #3778BF ΔE 0.039
- Mid Blue #276AB3 ΔE 0.049
- Cerulean Blue #056EEE ΔE 0.050
- French Blue #436BAD ΔE 0.054
- Neon Blue #4361EE ΔE 0.060
- Warm Blue #4B57DB ΔE 0.063
- Dark Periwinkle #665FD1 ΔE 0.063
Use #366FD0 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.