#1C66CB
Closest named color: Mid Blue (#276AB3). oklch(52.5% 0.172 258), rgb(28, 102, 203).
Aa
White text reads best on this color (5.50:1).
About this color
#1C66CB is a medium-dark, vivid blue. In OKLCH its lightness is 52%, its chroma 0.172 and its hue 258°. Its hue sits on the cool side of the wheel. The nearest named color is Mid Blue (#276AB3), ΔE 0.041 away. White text reads best on it, at 5.50:1.
| Hue family | Blues |
| Lightness | medium-dark (52%) |
| Chroma | vivid (0.172) |
| Temperature | cool |
| Nearest name | Mid Blue (#276AB3) |
| Black text | 3.81:1 |
| White text | 5.50:1 |
Values
| HEX | #1C66CB |
| RGB | rgb(28, 102, 203) |
| HSL | hsl(215, 76%, 45%) |
| OKLCH | oklch(52.5% 0.172 258) |
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 #1C66CB | 5.50:1 | AA | Lc -82.2 | Fine for body text |
| Black text on #1C66CB | 3.81:1 | AA large text | Lc 27.2 | Dividers and decoration only |
| #1C66CB text on white | 5.50:1 | AA | Lc 76.9 | Fine for body text |
| #1C66CB text on black | 3.81:1 | AA large text | Lc -24.8 | 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
#E1EBF9
oklch(93.7% 0.022 256.7)
-
Step 200
200
#C8DBF6
oklch(88.6% 0.043 257.1)
-
Step 300
300
#A2C3F3
oklch(81% 0.077 257.7)
-
Step 400
400
#6FA2ED
oklch(70.8% 0.123 257.9)
-
Step 500
500
#4788E7
oklch(63% 0.158 258)
-
Step 600
600 (this color)
#1C66CB
oklch(52.5% 0.172 258)
-
Step 700
700
#195DB9
oklch(49.1% 0.16 257.8)
-
Step 800
800
#184C96
oklch(42.7% 0.133 258.2)
-
Step 900
900
#1A4077
oklch(37.6% 0.104 258)
-
Step 950
950
#102646
oklch(27% 0.066 257.9)
#1C66CB 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) | #2671CF | 0.031 |
| Deuteranopia (no green cones) | #0062C9 | 0.016 |
| Tritanopia (no blue cones) | #007F8F | 0.131 |
| Achromatopsia (no color) | #696969 | 0.172 |
Harmonies
Hue rotations in OKLCH that keep this color's lightness and chroma.
Complementary
The opposite hue (180°).
- #1C66CB
#1C66CB
oklch(52.5% 0.172 258)
- #8D6100
#8D6100
oklch(52.6% 0.11 77.8)
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 #1C66CB, closest first.
Similar named colors
The eight closest entries in our named color list, with their ΔE distance.
- Mid Blue #276AB3 ΔE 0.041
- Royal Blue #4169E1 ΔE 0.047
- Cerulean Blue #056EEE ΔE 0.056
- Azul #1D5DEC ΔE 0.056
- Warm Blue #4B57DB ΔE 0.057
- French Blue #436BAD ΔE 0.059
- Windows Blue #3778BF ΔE 0.061
- Neon Blue #4361EE ΔE 0.064
Use #1C66CB 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.