#337FA4
Closest named color: Cerulean (#457B9D). oklch(56.6% 0.093 233.1), rgb(51, 127, 164).
Aa
Black text reads best on this color (4.71:1).
About this color
#337FA4 is a medium-dark, moderately saturated blue. In OKLCH its lightness is 57%, its chroma 0.093 and its hue 233°. Its hue sits on the cool side of the wheel. The nearest named color is Cerulean (#457B9D), ΔE 0.018 away. Black text reads best on it, at 4.71:1.
| Hue family | Blues |
| Lightness | medium-dark (57%) |
| Chroma | moderately saturated (0.093) |
| Temperature | cool |
| Nearest name | Cerulean (#457B9D) |
| Black text | 4.71:1 |
| White text | 4.45:1 |
Values
| HEX | #337FA4 |
| RGB | rgb(51, 127, 164) |
| HSL | hsl(200, 53%, 42%) |
| OKLCH | oklch(56.6% 0.093 233.1) |
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 #337FA4 | 4.45:1 | AA large text | Lc -76.1 | Fine for body text |
| Black text on #337FA4 | 4.71:1 | AA | Lc 33.4 | Non-text elements, placeholder text |
| #337FA4 text on white | 4.45:1 | AA large text | Lc 70.7 | Content text, not long reading |
| #337FA4 text on black | 4.71:1 | AA | Lc -31.0 | 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
#CBDCE6
oklch(88.5% 0.023 233.4)
-
Step 300
300
#A7C6D8
oklch(81% 0.042 233.5)
-
Step 400
400
#76A8C4
oklch(70.6% 0.067 233.5)
-
Step 500
500
#5092B5
oklch(63% 0.086 233.5)
-
Step 600
600 (this color)
#337FA4
oklch(56.6% 0.093 233.1)
-
Step 700
700
#21698A
oklch(49.2% 0.087 232.6)
-
Step 800
800
#1E5570
oklch(42.6% 0.072 233.6)
-
Step 900
900
#1F475B
oklch(37.8% 0.056 232.7)
-
Step 950
950
#132935
oklch(26.9% 0.036 234.1)
#337FA4 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) | #6D7EA6 | 0.061 |
| Deuteranopia (no green cones) | #5D72A3 | 0.052 |
| Tritanopia (no blue cones) | #00898B | 0.060 |
| Achromatopsia (no color) | #777777 | 0.093 |
Harmonies
Hue rotations in OKLCH that keep this color's lightness and chroma.
Complementary
The opposite hue (180°).
- #337FA4
#337FA4
oklch(56.6% 0.093 233.1)
- #A1663F
#A1663F
oklch(56.6% 0.093 53.2)
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 #337FA4, closest first.
Similar named colors
The eight closest entries in our named color list, with their ΔE distance.
- Cerulean #457B9D ΔE 0.018
- Stormy Blue #507B9C ΔE 0.027
- Dull Blue #49759C ΔE 0.031
- Steel Blue #4682B4 ΔE 0.032
- Nice Blue #107AB0 ΔE 0.032
- Teal Blue #01889F ΔE 0.033
- Blue NCS #118AB2 ΔE 0.034
- Flat Blue #3C73A8 ΔE 0.037
Use #337FA4 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.