#337FDF
Closest named color: Water Blue (#0E87CC). oklch(59.9% 0.164 256), rgb(51, 127, 223).
Aa
Black text reads best on this color (5.24:1).
About this color
#337FDF is a medium-dark, vivid blue. In OKLCH its lightness is 60%, its chroma 0.164 and its hue 256°. Its hue sits on the cool side of the wheel. The nearest named color is Water Blue (#0E87CC), ΔE 0.042 away. Black text reads best on it, at 5.24:1.
| Hue family | Blues |
| Lightness | medium-dark (60%) |
| Chroma | vivid (0.164) |
| Temperature | cool |
| Nearest name | Water Blue (#0E87CC) |
| Black text | 5.24:1 |
| White text | 4.00:1 |
Values
| HEX | #337FDF |
| RGB | rgb(51, 127, 223) |
| HSL | hsl(213, 73%, 54%) |
| OKLCH | oklch(59.9% 0.164 256) |
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 #337FDF | 4.00:1 | AA large text | Lc -72.4 | Content text, not long reading |
| Black text on #337FDF | 5.24:1 | AA | Lc 37.2 | Non-text elements, placeholder text |
| #337FDF text on white | 4.00:1 | AA large text | Lc 66.9 | Content text, not long reading |
| #337FDF text on black | 5.24:1 | AA | Lc -34.7 | 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 500.
-
Step 50
50
#F1F6FD
oklch(97.1% 0.011 256.7)
-
Step 100
100
#E0EBFA
oklch(93.6% 0.024 256.1)
-
Step 200
200
#C6DBF7
oklch(88.5% 0.045 255.6)
-
Step 300
300
#9FC3F4
oklch(80.8% 0.08 256.2)
-
Step 400
400
#69A3EF
oklch(70.8% 0.128 255.7)
-
Step 500
500 (this color)
#337FDF
oklch(59.9% 0.164 256)
-
Step 600
600
#1670D8
oklch(55.5% 0.178 256.1)
-
Step 700
700
#035DBC
oklch(49% 0.167 256.2)
-
Step 800
800
#0B4D98
oklch(42.8% 0.137 256)
-
Step 900
900
#144179
oklch(37.8% 0.107 256)
-
Step 950
950
#0D2647
oklch(26.9% 0.069 256.4)
#337FDF 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) | #4F87E3 | 0.034 |
| Deuteranopia (no green cones) | #2D78DD | 0.020 |
| Tritanopia (no blue cones) | #0096A4 | 0.126 |
| Achromatopsia (no color) | #7F7F7F | 0.164 |
Harmonies
Hue rotations in OKLCH that keep this color's lightness and chroma.
Complementary
The opposite hue (180°).
- #337FDF
#337FDF
oklch(59.9% 0.164 256)
- #AA7400
#AA7400
oklch(60% 0.126 76.4)
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 #337FDF, closest first.
Similar named colors
The eight closest entries in our named color list, with their ΔE distance.
- Water Blue #0E87CC ΔE 0.042
- Dark Sky Blue #448EE4 ΔE 0.044
- Clear Blue #247AFD ΔE 0.049
- Windows Blue #3778BF ΔE 0.050
- Royal Blue #4169E1 ΔE 0.056
- Soft Blue #6488EA ΔE 0.057
- Cerulean Blue #056EEE ΔE 0.058
- Dodger Blue #1E90FF ΔE 0.060
Use #337FDF 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.