#337DA4
Closest named color: Cerulean (#457B9D). oklch(56.1% 0.094 235.1), rgb(51, 125, 164).
Aa
Black text reads best on this color (4.61:1).
About this color
#337DA4 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 0.017 away. Black 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 | 4.61:1 |
| White text | 4.55:1 |
Values
| HEX | #337DA4 |
| RGB | rgb(51, 125, 164) |
| HSL | hsl(201, 53%, 42%) |
| OKLCH | oklch(56.1% 0.094 235.1) |
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 #337DA4 | 4.55:1 | AA | Lc -76.8 | Fine for body text |
| Black text on #337DA4 | 4.61:1 | AA | Lc 32.7 | Non-text elements, placeholder text |
| #337DA4 text on white | 4.55:1 | AA | Lc 71.4 | Content text, not long reading |
| #337DA4 text on black | 4.61:1 | AA | Lc -30.3 | 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
#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
#A7C6D9
oklch(81% 0.043 235)
-
Step 400
400
#76A8C5
oklch(70.7% 0.068 234.5)
-
Step 500
500
#5192B7
oklch(63.2% 0.087 235.4)
-
Step 600
600 (this color)
#337DA4
oklch(56.1% 0.094 235.1)
-
Step 700
700
#23688B
oklch(49.1% 0.088 234.9)
-
Step 800
800
#1F5571
oklch(42.7% 0.073 234.9)
-
Step 900
900
#20465B
oklch(37.6% 0.056 235.2)
-
Step 950
950
#142935
oklch(26.9% 0.035 235.2)
#337DA4 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) | #6A7CA6 | 0.058 |
| Deuteranopia (no green cones) | #5B71A3 | 0.049 |
| Tritanopia (no blue cones) | #00878A | 0.062 |
| Achromatopsia (no color) | #767676 | 0.094 |
Harmonies
Hue rotations in OKLCH that keep this color's lightness and chroma.
Complementary
The opposite hue (180°).
- #337DA4
#337DA4
oklch(56.1% 0.094 235.1)
- #9F653B
#9F653B
oklch(56.1% 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 #337DA4, closest first.
Similar named colors
The eight closest entries in our named color list, with their ΔE distance.
- Cerulean #457B9D ΔE 0.017
- Stormy Blue #507B9C ΔE 0.027
- Dull Blue #49759C ΔE 0.027
- Nice Blue #107AB0 ΔE 0.028
- Flat Blue #3C73A8 ΔE 0.032
- Steel Blue #4682B4 ΔE 0.033
- Muted Blue #3B719F ΔE 0.034
- Ocean #017B92 ΔE 0.038
Use #337DA4 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.