#257CCF
Closest named color: Windows Blue (#3778BF). oklch(57.8% 0.151 251.5), rgb(37, 124, 207).
Aa
Black text reads best on this color (4.86:1).
About this color
#257CCF is a medium-dark, vivid blue. In OKLCH its lightness is 58%, its chroma 0.151 and its hue 252°. Its hue sits on the cool side of the wheel. The nearest named color is Windows Blue (#3778BF), ΔE 0.026 away. Black text reads best on it, at 4.86:1.
| Hue family | Blues |
| Lightness | medium-dark (58%) |
| Chroma | vivid (0.151) |
| Temperature | cool |
| Nearest name | Windows Blue (#3778BF) |
| Black text | 4.86:1 |
| White text | 4.31:1 |
Values
| HEX | #257CCF |
| RGB | rgb(37, 124, 207) |
| HSL | hsl(209, 70%, 48%) |
| OKLCH | oklch(57.8% 0.151 251.5) |
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 #257CCF | 4.31:1 | AA large text | Lc -74.9 | Content text, not long reading |
| Black text on #257CCF | 4.86:1 | AA | Lc 34.7 | Non-text elements, placeholder text |
| #257CCF text on white | 4.31:1 | AA large text | Lc 69.4 | Content text, not long reading |
| #257CCF text on black | 4.86:1 | 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
#F1F6FC
oklch(97.1% 0.01 252.8)
-
Step 100
100
#E1EBF7
oklch(93.6% 0.019 252.9)
-
Step 200
200
#C8DBF2
oklch(88.4% 0.038 253.2)
-
Step 300
300
#A1C4EC
oklch(80.9% 0.068 252)
-
Step 400
400
#6CA5E2
oklch(70.7% 0.108 251.1)
-
Step 500
500
#428DDA
oklch(63.2% 0.138 251.4)
-
Step 600
600 (this color)
#257CCF
oklch(57.8% 0.151 251.5)
-
Step 700
700
#0A62AC
oklch(49.1% 0.139 251.3)
-
Step 800
800
#10508C
oklch(42.7% 0.117 251.9)
-
Step 900
900
#174370
oklch(37.7% 0.091 252)
-
Step 950
950
#0F2841
oklch(27.1% 0.056 250.6)
#257CCF 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) | #5382D2 | 0.043 |
| Deuteranopia (no green cones) | #3773CD | 0.024 |
| Tritanopia (no blue cones) | #00909B | 0.112 |
| Achromatopsia (no color) | #7A7A7A | 0.151 |
Harmonies
Hue rotations in OKLCH that keep this color's lightness and chroma.
Complementary
The opposite hue (180°).
- #257CCF
#257CCF
oklch(57.8% 0.151 251.5)
- #A76B00
#A76B00
oklch(57.8% 0.124 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 #257CCF, closest first.
Similar named colors
The eight closest entries in our named color list, with their ΔE distance.
- Windows Blue #3778BF ΔE 0.026
- Water Blue #0E87CC ΔE 0.032
- Nice Blue #107AB0 ΔE 0.050
- Cool Blue #4984B8 ΔE 0.053
- Steel Blue #4682B4 ΔE 0.054
- Royal Blue #4169E1 ΔE 0.061
- Flat Blue #3C73A8 ΔE 0.061
- Mid Blue #276AB3 ΔE 0.061
Use #257CCF 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.