#337CB8
Closest named color: Windows Blue (#3778BF). oklch(56.9% 0.118 246.7), rgb(51, 124, 184).
Aa
Black text reads best on this color (4.71:1).
About this color
#337CB8 is a medium-dark, moderately saturated blue. In OKLCH its lightness is 57%, its chroma 0.118 and its hue 247°. Its hue sits on the cool side of the wheel. The nearest named color is Windows Blue (#3778BF), ΔE 0.018 away. Black text reads best on it, at 4.71:1.
| Hue family | Blues |
| Lightness | medium-dark (57%) |
| Chroma | moderately saturated (0.118) |
| Temperature | cool |
| Nearest name | Windows Blue (#3778BF) |
| Black text | 4.71:1 |
| White text | 4.45:1 |
Values
| HEX | #337CB8 |
| RGB | rgb(51, 124, 184) |
| HSL | hsl(207, 57%, 46%) |
| OKLCH | oklch(56.9% 0.118 246.7) |
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 #337CB8 | 4.45:1 | AA large text | Lc -76.1 | Fine for body text |
| Black text on #337CB8 | 4.71:1 | AA | Lc 33.5 | Non-text elements, placeholder text |
| #337CB8 text on white | 4.45:1 | AA large text | Lc 70.6 | Content text, not long reading |
| #337CB8 text on black | 4.71:1 | AA | Lc -31.1 | 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
#CADCEC
oklch(88.6% 0.029 244.9)
-
Step 300
300
#A6C5E2
oklch(81% 0.053 246.7)
-
Step 400
400
#74A6D3
oklch(70.7% 0.085 246.5)
-
Step 500
500
#4E8FC7
oklch(63.1% 0.108 246.6)
-
Step 600
600 (this color)
#337CB8
oklch(56.9% 0.118 246.7)
-
Step 700
700
#21659B
oklch(49.2% 0.109 246.8)
-
Step 800
800
#1D527D
oklch(42.5% 0.091 246.7)
-
Step 900
900
#1E4465
oklch(37.6% 0.071 247.3)
-
Step 950
950
#13283B
oklch(26.9% 0.045 247.5)
#337CB8 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) | #617EBB | 0.047 |
| Deuteranopia (no green cones) | #4E72B7 | 0.034 |
| Tritanopia (no blue cones) | #008A91 | 0.086 |
| Achromatopsia (no color) | #777777 | 0.118 |
Harmonies
Hue rotations in OKLCH that keep this color's lightness and chroma.
Complementary
The opposite hue (180°).
- #337CB8
#337CB8
oklch(56.9% 0.118 246.7)
- #A56717
#A56717
oklch(56.9% 0.118 66.4)
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 #337CB8, closest first.
Similar named colors
The eight closest entries in our named color list, with their ΔE distance.
- Windows Blue #3778BF ΔE 0.018
- Nice Blue #107AB0 ΔE 0.023
- Steel Blue #4682B4 ΔE 0.027
- Flat Blue #3C73A8 ΔE 0.031
- Cool Blue #4984B8 ΔE 0.032
- Water Blue #0E87CC ΔE 0.039
- Cerulean #457B9D ΔE 0.043
- Muted Blue #3B719F ΔE 0.044
Use #337CB8 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.