#237EA3
Closest named color: Cerulean (#457B9D). oklch(55.8% 0.1 230.2), rgb(35, 126, 163).
Aa
Black text reads best on this color (4.58:1).
About this color
#237EA3 is a medium-dark, moderately saturated blue. In OKLCH its lightness is 56%, its chroma 0.100 and its hue 230°. Its hue sits on the cool side of the wheel. The nearest named color is Cerulean (#457B9D), ΔE 0.025 away. Black text reads best on it, at 4.58:1.
| Hue family | Blues |
| Lightness | medium-dark (56%) |
| Chroma | moderately saturated (0.100) |
| Temperature | cool |
| Nearest name | Cerulean (#457B9D) |
| Black text | 4.58:1 |
| White text | 4.58:1 |
Values
| HEX | #237EA3 |
| RGB | rgb(35, 126, 163) |
| HSL | hsl(197, 65%, 39%) |
| OKLCH | oklch(55.8% 0.1 230.2) |
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 #237EA3 | 4.58:1 | AA | Lc -76.9 | Fine for body text |
| Black text on #237EA3 | 4.58:1 | AA | Lc 32.6 | Non-text elements, placeholder text |
| #237EA3 text on white | 4.58:1 | AA | Lc 71.5 | Content text, not long reading |
| #237EA3 text on black | 4.58:1 | AA | Lc -30.2 | 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
#F2F6F9
oklch(97.1% 0.006 239.8)
-
Step 100
100
#E2ECF1
oklch(93.7% 0.013 228.9)
-
Step 200
200
#C9DDE7
oklch(88.6% 0.025 229.2)
-
Step 300
300
#A4C7D8
oklch(81% 0.044 228.9)
-
Step 400
400
#71A9C5
oklch(70.6% 0.071 230.8)
-
Step 500
500
#4794B6
oklch(63.2% 0.091 229.5)
-
Step 600
600 (this color)
#237EA3
oklch(55.8% 0.1 230.2)
-
Step 700
700
#126A8B
oklch(49.2% 0.092 229.8)
-
Step 800
800
#145671
oklch(42.6% 0.077 230.6)
-
Step 900
900
#1A475B
oklch(37.6% 0.059 230.5)
-
Step 950
950
#112A35
oklch(27.1% 0.037 229)
#237EA3 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) | #6B7CA5 | 0.068 |
| Deuteranopia (no green cones) | #5A70A2 | 0.058 |
| Tritanopia (no blue cones) | #00888A | 0.058 |
| Achromatopsia (no color) | #757575 | 0.100 |
Harmonies
Hue rotations in OKLCH that keep this color's lightness and chroma.
Complementary
The opposite hue (180°).
- #237EA3
#237EA3
oklch(55.8% 0.1 230.2)
- #A2613B
#A2613B
oklch(55.7% 0.1 49.9)
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 #237EA3, closest first.
Similar named colors
The eight closest entries in our named color list, with their ΔE distance.
- Cerulean #457B9D ΔE 0.025
- Nice Blue #107AB0 ΔE 0.027
- Ocean #017B92 ΔE 0.031
- Teal Blue #01889F ΔE 0.033
- Dull Blue #49759C ΔE 0.035
- Stormy Blue #507B9C ΔE 0.035
- Blue NCS #118AB2 ΔE 0.037
- Flat Blue #3C73A8 ΔE 0.037
Use #237EA3 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.