#257DB9
Closest named color: Nice Blue (#107AB0). oklch(56.8% 0.123 243.7), rgb(37, 125, 185).
Aa
Black text reads best on this color (4.71:1).
About this color
#257DB9 is a medium-dark, moderately saturated blue. In OKLCH its lightness is 57%, its chroma 0.123 and its hue 244°. Its hue sits on the cool side of the wheel. The nearest named color is Nice Blue (#107AB0), ΔE 0.019 away. Black text reads best on it, at 4.71:1.
| Hue family | Blues |
| Lightness | medium-dark (57%) |
| Chroma | moderately saturated (0.123) |
| Temperature | cool |
| Nearest name | Nice Blue (#107AB0) |
| Black text | 4.71:1 |
| White text | 4.45:1 |
Values
| HEX | #257DB9 |
| RGB | rgb(37, 125, 185) |
| HSL | hsl(204, 67%, 44%) |
| OKLCH | oklch(56.8% 0.123 243.7) |
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 #257DB9 | 4.45:1 | AA large text | Lc -76.0 | Fine for body text |
| Black text on #257DB9 | 4.71:1 | AA | Lc 33.6 | Non-text elements, placeholder text |
| #257DB9 text on white | 4.45:1 | AA large text | Lc 70.5 | Content text, not long reading |
| #257DB9 text on black | 4.71:1 | AA | Lc -31.1 | 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
#F1F6FA
oklch(97.1% 0.008 241.7)
-
Step 100
100
#E1EBF4
oklch(93.5% 0.016 245.1)
-
Step 200
200
#C9DCEC
oklch(88.5% 0.03 243.4)
-
Step 300
300
#A3C5E2
oklch(80.8% 0.055 244.3)
-
Step 400
400
#6FA7D4
oklch(70.7% 0.089 243.7)
-
Step 500
500
#4590C8
oklch(63% 0.113 243.6)
-
Step 600
600 (this color)
#257DB9
oklch(56.8% 0.123 243.7)
-
Step 700
700
#10669C
oklch(49.1% 0.114 243.7)
-
Step 800
800
#13537E
oklch(42.6% 0.094 243.8)
-
Step 900
900
#194566
oklch(37.7% 0.074 244.5)
-
Step 950
950
#10293B
oklch(27.1% 0.046 242.4)
#257DB9 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) | #617FBC | 0.055 |
| Deuteranopia (no green cones) | #4C71B8 | 0.042 |
| Tritanopia (no blue cones) | #008C92 | 0.086 |
| Achromatopsia (no color) | #777777 | 0.123 |
Harmonies
Hue rotations in OKLCH that keep this color's lightness and chroma.
Complementary
The opposite hue (180°).
- #257DB9
#257DB9
oklch(56.8% 0.123 243.7)
- #A86412
#A86412
oklch(56.7% 0.123 63.4)
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 #257DB9, closest first.
Similar named colors
The eight closest entries in our named color list, with their ΔE distance.
- Nice Blue #107AB0 ΔE 0.019
- Windows Blue #3778BF ΔE 0.021
- Steel Blue #4682B4 ΔE 0.031
- Flat Blue #3C73A8 ΔE 0.035
- Water Blue #0E87CC ΔE 0.036
- Cool Blue #4984B8 ΔE 0.036
- Blue NCS #118AB2 ΔE 0.042
- Cerulean #457B9D ΔE 0.046
Use #257DB9 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.