#2573BB
Closest named color: Windows Blue (#3778BF). oklch(54.5% 0.135 250.5), rgb(37, 115, 187).
Aa
White text reads best on this color (4.94:1).
About this color
#2573BB is a medium-dark, moderately saturated blue. In OKLCH its lightness is 55%, its chroma 0.135 and its hue 250°. Its hue sits on the cool side of the wheel. The nearest named color is Windows Blue (#3778BF), ΔE 0.021 away. White text reads best on it, at 4.94:1.
| Hue family | Blues |
| Lightness | medium-dark (55%) |
| Chroma | moderately saturated (0.135) |
| Temperature | cool |
| Nearest name | Windows Blue (#3778BF) |
| Black text | 4.24:1 |
| White text | 4.94:1 |
Values
| HEX | #2573BB |
| RGB | rgb(37, 115, 187) |
| HSL | hsl(209, 67%, 44%) |
| OKLCH | oklch(54.5% 0.135 250.5) |
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 #2573BB | 4.94:1 | AA | Lc -79.2 | Fine for body text |
| Black text on #2573BB | 4.24:1 | AA large text | Lc 30.3 | Non-text elements, placeholder text |
| #2573BB text on white | 4.94:1 | AA | Lc 73.8 | Content text, not long reading |
| #2573BB text on black | 4.24:1 | AA large text | Lc -27.9 | Dividers and decoration only |
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
#E1EBF5
oklch(93.5% 0.017 248)
-
Step 200
200
#C9DBEF
oklch(88.4% 0.034 251)
-
Step 300
300
#A4C4E7
oklch(80.9% 0.061 250.9)
-
Step 400
400
#71A5DB
oklch(70.7% 0.097 250.2)
-
Step 500
500
#4A8DD1
oklch(63% 0.124 250.7)
-
Step 600
600 (this color)
#2573BB
oklch(54.5% 0.135 250.5)
-
Step 700
700
#1B63A4
oklch(49.1% 0.125 250.4)
-
Step 800
800
#195185
oklch(42.7% 0.104 250.4)
-
Step 900
900
#1C446B
oklch(37.8% 0.081 250.3)
-
Step 950
950
#11283E
oklch(27% 0.05 249.3)
#2573BB 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) | #5178BE | 0.043 |
| Deuteranopia (no green cones) | #396ABA | 0.026 |
| Tritanopia (no blue cones) | #00848E | 0.098 |
| Achromatopsia (no color) | #707070 | 0.135 |
Harmonies
Hue rotations in OKLCH that keep this color's lightness and chroma.
Complementary
The opposite hue (180°).
- #2573BB
#2573BB
oklch(54.5% 0.135 250.5)
- #9B6200
#9B6200
oklch(54.6% 0.118 70.3)
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 #2573BB, closest first.
Similar named colors
The eight closest entries in our named color list, with their ΔE distance.
- Windows Blue #3778BF ΔE 0.021
- Mid Blue #276AB3 ΔE 0.026
- Nice Blue #107AB0 ΔE 0.030
- French Blue #436BAD ΔE 0.033
- Flat Blue #3C73A8 ΔE 0.033
- Muted Blue #3B719F ΔE 0.045
- Ocean Blue #03719C ΔE 0.052
- Steel Blue #4682B4 ΔE 0.056
Use #2573BB 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.