#337FA9
Closest named color: Cerulean (#457B9D). oklch(56.8% 0.098 236.5), rgb(51, 127, 169).
Aa
Black text reads best on this color (4.74:1).
About this color
#337FA9 is a medium-dark, moderately saturated blue. In OKLCH its lightness is 57%, its chroma 0.098 and its hue 236°. Its hue sits on the cool side of the wheel. The nearest named color is Cerulean (#457B9D), ΔE 0.022 away. Black text reads best on it, at 4.74:1.
| Hue family | Blues |
| Lightness | medium-dark (57%) |
| Chroma | moderately saturated (0.098) |
| Temperature | cool |
| Nearest name | Cerulean (#457B9D) |
| Black text | 4.74:1 |
| White text | 4.42:1 |
Values
| HEX | #337FA9 |
| RGB | rgb(51, 127, 169) |
| HSL | hsl(201, 54%, 43%) |
| OKLCH | oklch(56.8% 0.098 236.5) |
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 #337FA9 | 4.42:1 | AA large text | Lc -75.9 | Fine for body text |
| Black text on #337FA9 | 4.74:1 | AA | Lc 33.7 | Non-text elements, placeholder text |
| #337FA9 text on white | 4.42:1 | AA large text | Lc 70.4 | Content text, not long reading |
| #337FA9 text on black | 4.74:1 | AA | Lc -31.3 | 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
#CBDCE8
oklch(88.5% 0.025 238.4)
-
Step 300
300
#A6C6DA
oklch(81% 0.045 235.5)
-
Step 400
400
#75A8C7
oklch(70.7% 0.071 235.8)
-
Step 500
500
#4F92B9
oklch(63.2% 0.09 236.1)
-
Step 600
600 (this color)
#337FA9
oklch(56.8% 0.098 236.5)
-
Step 700
700
#20688E
oklch(49.2% 0.092 236.5)
-
Step 800
800
#1E5573
oklch(42.8% 0.075 236.4)
-
Step 900
900
#1F465D
oklch(37.7% 0.059 237.1)
-
Step 950
950
#132936
oklch(26.9% 0.037 236.3)
#337FA9 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) | #6B7EAB | 0.058 |
| Deuteranopia (no green cones) | #5B73A8 | 0.048 |
| Tritanopia (no blue cones) | #008A8D | 0.066 |
| Achromatopsia (no color) | #787878 | 0.098 |
Harmonies
Hue rotations in OKLCH that keep this color's lightness and chroma.
Complementary
The opposite hue (180°).
- #337FA9
#337FA9
oklch(56.8% 0.098 236.5)
- #A26739
#A26739
oklch(56.8% 0.098 57)
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 #337FA9, closest first.
Similar named colors
The eight closest entries in our named color list, with their ΔE distance.
- Cerulean #457B9D ΔE 0.022
- Steel Blue #4682B4 ΔE 0.026
- Nice Blue #107AB0 ΔE 0.028
- Stormy Blue #507B9C ΔE 0.030
- Blue NCS #118AB2 ΔE 0.032
- Dull Blue #49759C ΔE 0.033
- Cool Blue #4984B8 ΔE 0.034
- Flat Blue #3C73A8 ΔE 0.034
Use #337FA9 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.