#337CA3
Closest named color: Cerulean (#457B9D). oklch(55.8% 0.094 235.4), rgb(51, 124, 163).
Aa
White text reads best on this color (4.61:1).
About this color
#337CA3 is a medium-dark, moderately saturated blue. In OKLCH its lightness is 56%, its chroma 0.094 and its hue 235°. Its hue sits on the cool side of the wheel. The nearest named color is Cerulean (#457B9D), ΔE 0.016 away. White text reads best on it, at 4.61:1.
| Hue family | Blues |
| Lightness | medium-dark (56%) |
| Chroma | moderately saturated (0.094) |
| Temperature | cool |
| Nearest name | Cerulean (#457B9D) |
| Black text | 4.55:1 |
| White text | 4.61:1 |
Values
| HEX | #337CA3 |
| RGB | rgb(51, 124, 163) |
| HSL | hsl(201, 52%, 42%) |
| OKLCH | oklch(55.8% 0.094 235.4) |
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 #337CA3 | 4.61:1 | AA | Lc -77.2 | Fine for body text |
| Black text on #337CA3 | 4.55:1 | AA | Lc 32.3 | Non-text elements, placeholder text |
| #337CA3 text on white | 4.61:1 | AA | Lc 71.8 | Content text, not long reading |
| #337CA3 text on black | 4.55:1 | AA | Lc -29.9 | 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
#F2F6F9
oklch(97.1% 0.006 239.8)
-
Step 100
100
#E2EBF1
oklch(93.5% 0.013 236.6)
-
Step 200
200
#CBDCE7
oklch(88.5% 0.024 236)
-
Step 300
300
#A7C6D8
oklch(81% 0.042 233.5)
-
Step 400
400
#77A8C5
oklch(70.7% 0.067 235)
-
Step 500
500
#5192B6
oklch(63.1% 0.086 234.6)
-
Step 600
600 (this color)
#337CA3
oklch(55.8% 0.094 235.4)
-
Step 700
700
#24688B
oklch(49.1% 0.087 235.2)
-
Step 800
800
#205571
oklch(42.7% 0.072 235.2)
-
Step 900
900
#20465B
oklch(37.6% 0.056 235.2)
-
Step 950
950
#142935
oklch(26.9% 0.035 235.2)
#337CA3 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) | #697BA5 | 0.057 |
| Deuteranopia (no green cones) | #5A70A2 | 0.048 |
| Tritanopia (no blue cones) | #008689 | 0.062 |
| Achromatopsia (no color) | #757575 | 0.094 |
Harmonies
Hue rotations in OKLCH that keep this color's lightness and chroma.
Complementary
The opposite hue (180°).
- #337CA3
#337CA3
oklch(55.8% 0.094 235.4)
- #9E643A
#9E643A
oklch(55.8% 0.094 55.3)
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 #337CA3, closest first.
Similar named colors
The eight closest entries in our named color list, with their ΔE distance.
- Cerulean #457B9D ΔE 0.016
- Dull Blue #49759C ΔE 0.025
- Stormy Blue #507B9C ΔE 0.027
- Nice Blue #107AB0 ΔE 0.028
- Flat Blue #3C73A8 ΔE 0.030
- Muted Blue #3B719F ΔE 0.031
- Steel Blue #4682B4 ΔE 0.035
- Ocean #017B92 ΔE 0.037
Use #337CA3 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.