#337FB0
Closest named color: Steel Blue (#4682B4). oklch(57.2% 0.106 240.6), rgb(51, 127, 176).
Aa
Black text reads best on this color (4.80:1).
About this color
#337FB0 is a medium-dark, moderately saturated blue. In OKLCH its lightness is 57%, its chroma 0.106 and its hue 241°. Its hue sits on the cool side of the wheel. The nearest named color is Steel Blue (#4682B4), ΔE 0.020 away. Black text reads best on it, at 4.80:1.
| Hue family | Blues |
| Lightness | medium-dark (57%) |
| Chroma | moderately saturated (0.106) |
| Temperature | cool |
| Nearest name | Steel Blue (#4682B4) |
| Black text | 4.80:1 |
| White text | 4.37:1 |
Values
| HEX | #337FB0 |
| RGB | rgb(51, 127, 176) |
| HSL | hsl(204, 55%, 45%) |
| OKLCH | oklch(57.2% 0.106 240.6) |
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 #337FB0 | 4.37:1 | AA large text | Lc -75.5 | Fine for body text |
| Black text on #337FB0 | 4.80:1 | AA | Lc 34.1 | Non-text elements, placeholder text |
| #337FB0 text on white | 4.37:1 | AA large text | Lc 70.0 | Content text, not long reading |
| #337FB0 text on black | 4.80:1 | AA | Lc -31.7 | 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 600.
-
Step 50
50
#F2F6F9
oklch(97.1% 0.006 239.8)
-
Step 100
100
#E2EBF2
oklch(93.5% 0.014 241)
-
Step 200
200
#CADCE9
oklch(88.5% 0.026 239.1)
-
Step 300
300
#A6C5DD
oklch(80.9% 0.048 241.5)
-
Step 400
400
#75A7CC
oklch(70.7% 0.076 241.2)
-
Step 500
500
#4E91BF
oklch(63.2% 0.097 240.7)
-
Step 600
600 (this color)
#337FB0
oklch(57.2% 0.106 240.6)
-
Step 700
700
#1F6793
oklch(49.1% 0.099 240.5)
-
Step 800
800
#1D5477
oklch(42.7% 0.081 240.6)
-
Step 900
900
#1E4660
oklch(37.8% 0.063 239.9)
-
Step 950
950
#132938
oklch(27% 0.04 240.2)
#337FB0 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) | #687FB2 | 0.054 |
| Deuteranopia (no green cones) | #5773AF | 0.044 |
| Tritanopia (no blue cones) | #008B90 | 0.073 |
| Achromatopsia (no color) | #797979 | 0.106 |
Harmonies
Hue rotations in OKLCH that keep this color's lightness and chroma.
Complementary
The opposite hue (180°).
- #337FB0
#337FB0
oklch(57.2% 0.106 240.6)
- #A5682F
#A5682F
oklch(57.3% 0.106 60.9)
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 #337FB0, closest first.
Similar named colors
The eight closest entries in our named color list, with their ΔE distance.
- Steel Blue #4682B4 ΔE 0.020
- Nice Blue #107AB0 ΔE 0.025
- Cool Blue #4984B8 ΔE 0.027
- Cerulean #457B9D ΔE 0.030
- Blue NCS #118AB2 ΔE 0.032
- Flat Blue #3C73A8 ΔE 0.034
- Windows Blue #3778BF ΔE 0.034
- Stormy Blue #507B9C ΔE 0.036
Use #337FB0 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.