#337ABB
Closest named color: Windows Blue (#3778BF). oklch(56.6% 0.123 249.2), rgb(51, 122, 187).
Aa
Black text reads best on this color (4.64:1).
About this color
#337ABB is a medium-dark, moderately saturated blue. In OKLCH its lightness is 57%, its chroma 0.123 and its hue 249°. Its hue sits on the cool side of the wheel. The nearest named color is Windows Blue (#3778BF), ΔE 0.010 away. Black text reads best on it, at 4.64:1.
| Hue family | Blues |
| Lightness | medium-dark (57%) |
| Chroma | moderately saturated (0.123) |
| Temperature | cool |
| Nearest name | Windows Blue (#3778BF) |
| Black text | 4.64:1 |
| White text | 4.52:1 |
Values
| HEX | #337ABB |
| RGB | rgb(51, 122, 187) |
| HSL | hsl(209, 57%, 47%) |
| OKLCH | oklch(56.6% 0.123 249.2) |
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 #337ABB | 4.52:1 | AA | Lc -76.6 | Fine for body text |
| Black text on #337ABB | 4.64:1 | AA | Lc 33.0 | Non-text elements, placeholder text |
| #337ABB text on white | 4.52:1 | AA | Lc 71.1 | Content text, not long reading |
| #337ABB text on black | 4.64:1 | AA | Lc -30.6 | 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
#F2F6FA
oklch(97.1% 0.007 247.9)
-
Step 100
100
#E2EBF4
oklch(93.6% 0.016 248)
-
Step 200
200
#CADBED
oklch(88.4% 0.031 249.7)
-
Step 300
300
#A6C4E4
oklch(80.9% 0.056 250.2)
-
Step 400
400
#75A5D6
oklch(70.7% 0.089 249.7)
-
Step 500
500
#4F8ECB
oklch(63.1% 0.113 249.4)
-
Step 600
600 (this color)
#337ABB
oklch(56.6% 0.123 249.2)
-
Step 700
700
#22649E
oklch(49.1% 0.114 249)
-
Step 800
800
#1E5280
oklch(42.8% 0.094 248.7)
-
Step 900
900
#1F4467
oklch(37.7% 0.074 249.2)
-
Step 950
950
#13283C
oklch(27% 0.046 248.8)
#337ABB 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) | #5C7DBE | 0.042 |
| Deuteranopia (no green cones) | #4971BA | 0.029 |
| Tritanopia (no blue cones) | #008992 | 0.090 |
| Achromatopsia (no color) | #767676 | 0.123 |
Harmonies
Hue rotations in OKLCH that keep this color's lightness and chroma.
Complementary
The opposite hue (180°).
- #337ABB
#337ABB
oklch(56.6% 0.123 249.2)
- #A46700
#A46700
oklch(56.7% 0.123 69.5)
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 #337ABB, closest first.
Similar named colors
The eight closest entries in our named color list, with their ΔE distance.
- Windows Blue #3778BF ΔE 0.010
- Nice Blue #107AB0 ΔE 0.026
- Flat Blue #3C73A8 ΔE 0.032
- Steel Blue #4682B4 ΔE 0.033
- Cool Blue #4984B8 ΔE 0.038
- Water Blue #0E87CC ΔE 0.040
- French Blue #436BAD ΔE 0.043
- Muted Blue #3B719F ΔE 0.046
Use #337ABB 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.