#237AB4
Closest named color: Nice Blue (#107AB0). oklch(55.7% 0.12 243.2), rgb(35, 122, 180).
Aa
White text reads best on this color (4.65:1).
About this color
#237AB4 is a medium-dark, moderately saturated blue. In OKLCH its lightness is 56%, its chroma 0.120 and its hue 243°. Its hue sits on the cool side of the wheel. The nearest named color is Nice Blue (#107AB0), ΔE 0.010 away. White text reads best on it, at 4.65:1.
| Hue family | Blues |
| Lightness | medium-dark (56%) |
| Chroma | moderately saturated (0.120) |
| Temperature | cool |
| Nearest name | Nice Blue (#107AB0) |
| Black text | 4.51:1 |
| White text | 4.65:1 |
Values
| HEX | #237AB4 |
| RGB | rgb(35, 122, 180) |
| HSL | hsl(204, 67%, 42%) |
| OKLCH | oklch(55.7% 0.12 243.2) |
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 #237AB4 | 4.65:1 | AA | Lc -77.4 | Fine for body text |
| Black text on #237AB4 | 4.51:1 | AA | Lc 32.2 | Non-text elements, placeholder text |
| #237AB4 text on white | 4.65:1 | AA | Lc 71.9 | Content text, not long reading |
| #237AB4 text on black | 4.51:1 | AA | Lc -29.8 | 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
#F1F6FA
oklch(97.1% 0.008 241.7)
-
Step 100
100
#E1EBF4
oklch(93.5% 0.016 245.1)
-
Step 200
200
#C9DCEC
oklch(88.5% 0.03 243.4)
-
Step 300
300
#A3C5E1
oklch(80.8% 0.054 243.3)
-
Step 400
400
#70A7D3
oklch(70.7% 0.087 243.6)
-
Step 500
500
#4790C7
oklch(63% 0.111 243.7)
-
Step 600
600 (this color)
#237AB4
oklch(55.7% 0.12 243.2)
-
Step 700
700
#13669B
oklch(49.1% 0.112 243.6)
-
Step 800
800
#15537D
oklch(42.6% 0.092 243.6)
-
Step 900
900
#194565
oklch(37.6% 0.073 243.7)
-
Step 950
950
#10293B
oklch(27.1% 0.046 242.4)
#237AB4 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) | #5F7CB7 | 0.055 |
| Deuteranopia (no green cones) | #4B6EB3 | 0.042 |
| Tritanopia (no blue cones) | #00888F | 0.082 |
| Achromatopsia (no color) | #747474 | 0.120 |
Harmonies
Hue rotations in OKLCH that keep this color's lightness and chroma.
Complementary
The opposite hue (180°).
- #237AB4
#237AB4
oklch(55.7% 0.12 243.2)
- #A46213
#A46213
oklch(55.8% 0.12 63.5)
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 #237AB4, closest first.
Similar named colors
The eight closest entries in our named color list, with their ΔE distance.
- Nice Blue #107AB0 ΔE 0.010
- Windows Blue #3778BF ΔE 0.024
- Flat Blue #3C73A8 ΔE 0.026
- Steel Blue #4682B4 ΔE 0.037
- Muted Blue #3B719F ΔE 0.038
- Cerulean #457B9D ΔE 0.043
- Dull Blue #49759C ΔE 0.043
- Cool Blue #4984B8 ΔE 0.044
Use #237AB4 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.