#337FBA
Closest named color: Steel Blue (#4682B4). oklch(57.7% 0.117 245.5), rgb(51, 127, 186).
Aa
Black text reads best on this color (4.88:1).
About this color
#337FBA is a medium-dark, moderately saturated blue. In OKLCH its lightness is 58%, its chroma 0.117 and its hue 245°. Its hue sits on the cool side of the wheel. The nearest named color is Steel Blue (#4682B4), ΔE 0.021 away. Black text reads best on it, at 4.88:1.
| Hue family | Blues |
| Lightness | medium-dark (58%) |
| Chroma | moderately saturated (0.117) |
| Temperature | cool |
| Nearest name | Steel Blue (#4682B4) |
| Black text | 4.88:1 |
| White text | 4.29:1 |
Values
| HEX | #337FBA |
| RGB | rgb(51, 127, 186) |
| HSL | hsl(206, 57%, 46%) |
| OKLCH | oklch(57.7% 0.117 245.5) |
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 #337FBA | 4.29:1 | AA large text | Lc -74.9 | Content text, not long reading |
| Black text on #337FBA | 4.88:1 | AA | Lc 34.7 | Non-text elements, placeholder text |
| #337FBA text on white | 4.29:1 | AA large text | Lc 69.4 | Content text, not long reading |
| #337FBA text on black | 4.88:1 | AA | Lc -32.2 | 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
#F2F6FA
oklch(97.1% 0.007 247.9)
-
Step 100
100
#E2EBF4
oklch(93.6% 0.016 248)
-
Step 200
200
#CADCEC
oklch(88.6% 0.029 244.9)
-
Step 300
300
#A5C5E1
oklch(80.9% 0.053 244.9)
-
Step 400
400
#73A6D2
oklch(70.6% 0.085 245.4)
-
Step 500
500
#4C8FC7
oklch(63% 0.109 245.9)
-
Step 600
600 (this color)
#337FBA
oklch(57.7% 0.117 245.5)
-
Step 700
700
#1D659A
oklch(49% 0.109 245.5)
-
Step 800
800
#1B537D
oklch(42.7% 0.09 245.2)
-
Step 900
900
#1D4564
oklch(37.7% 0.07 244.6)
-
Step 950
950
#12283B
oklch(26.9% 0.045 246.6)
#337FBA 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) | #6481BD | 0.049 |
| Deuteranopia (no green cones) | #5174B9 | 0.037 |
| Tritanopia (no blue cones) | #008D94 | 0.084 |
| Achromatopsia (no color) | #7A7A7A | 0.117 |
Harmonies
Hue rotations in OKLCH that keep this color's lightness and chroma.
Complementary
The opposite hue (180°).
- #337FBA
#337FBA
oklch(57.7% 0.117 245.5)
- #A8691D
#A8691D
oklch(57.7% 0.118 65.4)
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 #337FBA, closest first.
Similar named colors
The eight closest entries in our named color list, with their ΔE distance.
- Steel Blue #4682B4 ΔE 0.021
- Windows Blue #3778BF ΔE 0.023
- Cool Blue #4984B8 ΔE 0.025
- Nice Blue #107AB0 ΔE 0.029
- Water Blue #0E87CC ΔE 0.032
- Blue NCS #118AB2 ΔE 0.038
- Flat Blue #3C73A8 ΔE 0.039
- Off Blue #5684AE ΔE 0.041
Use #337FBA 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.