#257BD9
Closest named color: Windows Blue (#3778BF). oklch(58.3% 0.164 254.2), rgb(37, 123, 217).
Aa
Black text reads best on this color (4.91:1).
About this color
#257BD9 is a medium-dark, vivid blue. In OKLCH its lightness is 58%, its chroma 0.164 and its hue 254°. Its hue sits on the cool side of the wheel. The nearest named color is Windows Blue (#3778BF), ΔE 0.040 away. Black text reads best on it, at 4.91:1.
| Hue family | Blues |
| Lightness | medium-dark (58%) |
| Chroma | vivid (0.164) |
| Temperature | cool |
| Nearest name | Windows Blue (#3778BF) |
| Black text | 4.91:1 |
| White text | 4.27:1 |
Values
| HEX | #257BD9 |
| RGB | rgb(37, 123, 217) |
| HSL | hsl(211, 71%, 50%) |
| OKLCH | oklch(58.3% 0.164 254.2) |
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 #257BD9 | 4.27:1 | AA large text | Lc -74.5 | Content text, not long reading |
| Black text on #257BD9 | 4.91:1 | AA | Lc 35.0 | Non-text elements, placeholder text |
| #257BD9 text on white | 4.27:1 | AA large text | Lc 69.0 | Content text, not long reading |
| #257BD9 text on black | 4.91:1 | AA | Lc -32.6 | 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
#E0EBF8
oklch(93.6% 0.021 252.5)
-
Step 200
200
#C7DBF4
oklch(88.4% 0.041 254)
-
Step 300
300
#A0C4F0
oklch(81% 0.074 253.7)
-
Step 400
400
#6BA4E9
oklch(70.8% 0.118 254)
-
Step 500
500
#408BE2
oklch(63.1% 0.151 254.1)
-
Step 600
600 (this color)
#257BD9
oklch(58.3% 0.164 254.2)
-
Step 700
700
#0960B4
oklch(49.2% 0.152 254.1)
-
Step 800
800
#0E4F92
oklch(42.8% 0.126 254)
-
Step 900
900
#164274
oklch(37.7% 0.098 254.2)
-
Step 950
950
#0E2744
oklch(27% 0.062 253.9)
#257BD9 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) | #4A83DD | 0.038 |
| Deuteranopia (no green cones) | #2673D7 | 0.021 |
| Tritanopia (no blue cones) | #00929F | 0.124 |
| Achromatopsia (no color) | #7A7A7A | 0.164 |
Harmonies
Hue rotations in OKLCH that keep this color's lightness and chroma.
Complementary
The opposite hue (180°).
- #257BD9
#257BD9
oklch(58.3% 0.164 254.2)
- #A66E00
#A66E00
oklch(58.3% 0.124 74)
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 #257BD9, closest first.
Similar named colors
The eight closest entries in our named color list, with their ΔE distance.
- Windows Blue #3778BF ΔE 0.040
- Water Blue #0E87CC ΔE 0.042
- Royal Blue #4169E1 ΔE 0.050
- Cerulean Blue #056EEE ΔE 0.051
- Clear Blue #247AFD ΔE 0.055
- Dark Sky Blue #448EE4 ΔE 0.060
- Nice Blue #107AB0 ΔE 0.065
- Cool Blue #4984B8 ΔE 0.067
Use #257BD9 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.