#237BCC
Closest named color: Windows Blue (#3778BF). oklch(57.4% 0.148 250.9), rgb(35, 123, 204).
Aa
Black text reads best on this color (4.77:1).
About this color
#237BCC is a medium-dark, vivid blue. In OKLCH its lightness is 57%, its chroma 0.148 and its hue 251°. Its hue sits on the cool side of the wheel. The nearest named color is Windows Blue (#3778BF), ΔE 0.022 away. Black text reads best on it, at 4.77:1.
| Hue family | Blues |
| Lightness | medium-dark (57%) |
| Chroma | vivid (0.148) |
| Temperature | cool |
| Nearest name | Windows Blue (#3778BF) |
| Black text | 4.77:1 |
| White text | 4.39:1 |
Values
| HEX | #237BCC |
| RGB | rgb(35, 123, 204) |
| HSL | hsl(209, 71%, 47%) |
| OKLCH | oklch(57.4% 0.148 250.9) |
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 #237BCC | 4.39:1 | AA large text | Lc -75.5 | Fine for body text |
| Black text on #237BCC | 4.77:1 | AA | Lc 34.1 | Non-text elements, placeholder text |
| #237BCC text on white | 4.39:1 | AA large text | Lc 70.0 | Content text, not long reading |
| #237BCC text on black | 4.77:1 | AA | Lc -31.7 | Non-text elements, placeholder text |
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
#F1F6FB
oklch(97.1% 0.009 247.9)
-
Step 100
100
#E1EBF7
oklch(93.6% 0.019 252.9)
-
Step 200
200
#C8DBF1
oklch(88.4% 0.037 252.1)
-
Step 300
300
#A1C4EB
oklch(80.8% 0.067 251.4)
-
Step 400
400
#6CA5E1
oklch(70.7% 0.107 250.7)
-
Step 500
500
#428DD9
oklch(63.1% 0.137 251.1)
-
Step 600
600 (this color)
#237BCC
oklch(57.4% 0.148 250.9)
-
Step 700
700
#0A62AB
oklch(49% 0.138 251)
-
Step 800
800
#0F518B
oklch(42.8% 0.114 250.7)
-
Step 900
900
#16436F
oklch(37.6% 0.09 251.1)
-
Step 950
950
#0F2841
oklch(27.1% 0.056 250.6)
#237BCC 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) | #5380CF | 0.043 |
| Deuteranopia (no green cones) | #3871CA | 0.028 |
| Tritanopia (no blue cones) | #008E99 | 0.109 |
| Achromatopsia (no color) | #787878 | 0.148 |
Harmonies
Hue rotations in OKLCH that keep this color's lightness and chroma.
Complementary
The opposite hue (180°).
- #237BCC
#237BCC
oklch(57.4% 0.148 250.9)
- #A56A00
#A56A00
oklch(57.4% 0.123 71.4)
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 #237BCC, closest first.
Similar named colors
The eight closest entries in our named color list, with their ΔE distance.
- Windows Blue #3778BF ΔE 0.022
- Water Blue #0E87CC ΔE 0.033
- Nice Blue #107AB0 ΔE 0.045
- Steel Blue #4682B4 ΔE 0.052
- Cool Blue #4984B8 ΔE 0.053
- Mid Blue #276AB3 ΔE 0.056
- Flat Blue #3C73A8 ΔE 0.056
- French Blue #436BAD ΔE 0.059
Use #237BCC 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.