#237AD9
Closest named color: Windows Blue (#3778BF). oklch(58% 0.166 254.3), rgb(35, 122, 217).
Aa
Black text reads best on this color (4.85:1).
About this color
#237AD9 is a medium-dark, vivid blue. In OKLCH its lightness is 58%, its chroma 0.166 and its hue 254°. Its hue sits on the cool side of the wheel. The nearest named color is Windows Blue (#3778BF), ΔE 0.040 away. Black text reads best on it, at 4.85:1.
| Hue family | Blues |
| Lightness | medium-dark (58%) |
| Chroma | vivid (0.166) |
| Temperature | cool |
| Nearest name | Windows Blue (#3778BF) |
| Black text | 4.85:1 |
| White text | 4.32:1 |
Values
| HEX | #237AD9 |
| RGB | rgb(35, 122, 217) |
| HSL | hsl(211, 72%, 49%) |
| OKLCH | oklch(58% 0.166 254.3) |
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 #237AD9 | 4.32:1 | AA large text | Lc -74.9 | Content text, not long reading |
| Black text on #237AD9 | 4.85:1 | AA | Lc 34.7 | Non-text elements, placeholder text |
| #237AD9 text on white | 4.32:1 | AA large text | Lc 69.4 | Content text, not long reading |
| #237AD9 text on black | 4.85:1 | AA | Lc -32.3 | 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
#F1F6FC
oklch(97.1% 0.01 252.8)
-
Step 100
100
#E0EBF8
oklch(93.6% 0.021 252.5)
-
Step 200
200
#C7DBF5
oklch(88.5% 0.042 255)
-
Step 300
300
#A0C4F1
oklch(81% 0.075 254.2)
-
Step 400
400
#6BA3E9
oklch(70.6% 0.119 254.6)
-
Step 500
500
#408BE3
oklch(63.2% 0.152 254.3)
-
Step 600
600 (this color)
#237AD9
oklch(58% 0.166 254.3)
-
Step 700
700
#075FB5
oklch(49% 0.155 254.5)
-
Step 800
800
#0D4E92
oklch(42.6% 0.128 254.3)
-
Step 900
900
#154275
oklch(37.8% 0.1 254.2)
-
Step 950
950
#0E2744
oklch(27% 0.062 253.9)
#237AD9 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) | #4882DD | 0.037 |
| Deuteranopia (no green cones) | #2172D7 | 0.022 |
| Tritanopia (no blue cones) | #00919F | 0.124 |
| Achromatopsia (no color) | #797979 | 0.166 |
Harmonies
Hue rotations in OKLCH that keep this color's lightness and chroma.
Complementary
The opposite hue (180°).
- #237AD9
#237AD9
oklch(58% 0.166 254.3)
- #A46D00
#A46D00
oklch(57.9% 0.122 74.2)
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 #237AD9, closest first.
Similar named colors
The eight closest entries in our named color list, with their ΔE distance.
- Windows Blue #3778BF ΔE 0.040
- Water Blue #0E87CC ΔE 0.044
- Royal Blue #4169E1 ΔE 0.048
- Cerulean Blue #056EEE ΔE 0.049
- Clear Blue #247AFD ΔE 0.055
- Dark Sky Blue #448EE4 ΔE 0.063
- Nice Blue #107AB0 ΔE 0.066
- Mid Blue #276AB3 ΔE 0.068
Use #237AD9 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.