#257ACB
Closest named color: Windows Blue (#3778BF). oklch(57.1% 0.148 251.4), rgb(37, 122, 203).
Aa
Black text reads best on this color (4.72:1).
About this color
#257ACB is a medium-dark, vivid blue. In OKLCH its lightness is 57%, its chroma 0.148 and its hue 251°. Its hue sits on the cool side of the wheel. The nearest named color is Windows Blue (#3778BF), ΔE 0.020 away. Black text reads best on it, at 4.72:1.
| Hue family | Blues |
| Lightness | medium-dark (57%) |
| Chroma | vivid (0.148) |
| Temperature | cool |
| Nearest name | Windows Blue (#3778BF) |
| Black text | 4.72:1 |
| White text | 4.44:1 |
Values
| HEX | #257ACB |
| RGB | rgb(37, 122, 203) |
| HSL | hsl(209, 69%, 47%) |
| OKLCH | oklch(57.1% 0.148 251.4) |
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 #257ACB | 4.44:1 | AA large text | Lc -75.9 | Fine for body text |
| Black text on #257ACB | 4.72:1 | AA | Lc 33.7 | Non-text elements, placeholder text |
| #257ACB text on white | 4.44:1 | AA large text | Lc 70.4 | Content text, not long reading |
| #257ACB text on black | 4.72:1 | 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
#F1F6FB
oklch(97.1% 0.009 247.9)
-
Step 100
100
#E1EBF7
oklch(93.6% 0.019 252.9)
-
Step 200
200
#C8DBF1
oklch(88.4% 0.037 252.1)
-
Step 300
300
#A2C4EB
oklch(80.9% 0.066 252.1)
-
Step 400
400
#6DA5E1
oklch(70.7% 0.106 251.1)
-
Step 500
500
#438DD8
oklch(63.1% 0.135 251.1)
-
Step 600
600 (this color)
#257ACB
oklch(57.1% 0.148 251.4)
-
Step 700
700
#0F62AB
oklch(49.1% 0.137 251.5)
-
Step 800
800
#12508A
oklch(42.6% 0.113 251.5)
-
Step 900
900
#18436F
oklch(37.7% 0.089 251.8)
-
Step 950
950
#0F2841
oklch(27.1% 0.056 250.6)
#257ACB 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) | #5280CE | 0.042 |
| Deuteranopia (no green cones) | #3771C9 | 0.025 |
| Tritanopia (no blue cones) | #008D98 | 0.109 |
| Achromatopsia (no color) | #787878 | 0.148 |
Harmonies
Hue rotations in OKLCH that keep this color's lightness and chroma.
Complementary
The opposite hue (180°).
- #257ACB
#257ACB
oklch(57.1% 0.148 251.4)
- #A46900
#A46900
oklch(57.1% 0.123 71.1)
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 #257ACB, closest first.
Similar named colors
The eight closest entries in our named color list, with their ΔE distance.
- Windows Blue #3778BF ΔE 0.020
- Water Blue #0E87CC ΔE 0.035
- Nice Blue #107AB0 ΔE 0.044
- Steel Blue #4682B4 ΔE 0.052
- Cool Blue #4984B8 ΔE 0.053
- Mid Blue #276AB3 ΔE 0.053
- Flat Blue #3C73A8 ΔE 0.054
- French Blue #436BAD ΔE 0.057
Use #257ACB 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.