#337FA1
Closest named color: Cerulean (#457B9D). oklch(56.4% 0.09 230.8), rgb(51, 127, 161).
Aa
Black text reads best on this color (4.69:1).
About this color
#337FA1 is a medium-dark, moderately saturated blue. In OKLCH its lightness is 56%, its chroma 0.090 and its hue 231°. Its hue sits on the cool side of the wheel. The nearest named color is Cerulean (#457B9D), ΔE 0.017 away. Black text reads best on it, at 4.69:1.
| Hue family | Blues |
| Lightness | medium-dark (56%) |
| Chroma | moderately saturated (0.090) |
| Temperature | cool |
| Nearest name | Cerulean (#457B9D) |
| Black text | 4.69:1 |
| White text | 4.47:1 |
Values
| HEX | #337FA1 |
| RGB | rgb(51, 127, 161) |
| HSL | hsl(199, 52%, 42%) |
| OKLCH | oklch(56.4% 0.09 230.8) |
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 #337FA1 | 4.47:1 | AA large text | Lc -76.3 | Fine for body text |
| Black text on #337FA1 | 4.69:1 | AA | Lc 33.3 | Non-text elements, placeholder text |
| #337FA1 text on white | 4.47:1 | AA large text | Lc 70.8 | Content text, not long reading |
| #337FA1 text on black | 4.69:1 | AA | Lc -30.9 | 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
#F2F6F8
oklch(97.1% 0.005 228.8)
-
Step 100
100
#E2EBF0
oklch(93.5% 0.012 231.7)
-
Step 200
200
#CBDCE6
oklch(88.5% 0.023 233.4)
-
Step 300
300
#A7C6D6
oklch(80.9% 0.04 230.3)
-
Step 400
400
#76A9C2
oklch(70.8% 0.065 230)
-
Step 500
500
#5093B3
oklch(63.2% 0.083 230.8)
-
Step 600
600 (this color)
#337FA1
oklch(56.4% 0.09 230.8)
-
Step 700
700
#226988
oklch(49.2% 0.084 231.1)
-
Step 800
800
#1F566E
oklch(42.8% 0.069 230.3)
-
Step 900
900
#1F4759
oklch(37.7% 0.054 229.9)
-
Step 950
950
#132A34
oklch(27.1% 0.034 228.3)
#337FA1 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) | #6E7DA3 | 0.062 |
| Deuteranopia (no green cones) | #5F72A1 | 0.054 |
| Tritanopia (no blue cones) | #00888A | 0.056 |
| Achromatopsia (no color) | #777777 | 0.091 |
Harmonies
Hue rotations in OKLCH that keep this color's lightness and chroma.
Complementary
The opposite hue (180°).
- #337FA1
#337FA1
oklch(56.4% 0.09 230.8)
- #A06542
#A06542
oklch(56.3% 0.091 50.7)
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 #337FA1, closest first.
Similar named colors
The eight closest entries in our named color list, with their ΔE distance.
- Cerulean #457B9D ΔE 0.017
- Stormy Blue #507B9C ΔE 0.026
- Dull Blue #49759C ΔE 0.031
- Teal Blue #01889F ΔE 0.031
- Ocean #017B92 ΔE 0.035
- Nice Blue #107AB0 ΔE 0.035
- Steel Blue #4682B4 ΔE 0.035
- Blue NCS #118AB2 ΔE 0.036
Use #337FA1 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.