#557BCB
Closest named color: Windows Blue (#3778BF). oklch(59.2% 0.13 263.7), rgb(85, 123, 203).
Aa
Black text reads best on this color (5.08:1).
About this color
#557BCB is a medium-dark, moderately saturated blue. In OKLCH its lightness is 59%, its chroma 0.130 and its hue 264°. Its hue sits on the cool side of the wheel. The nearest named color is Windows Blue (#3778BF), ΔE 0.037 away. Black text reads best on it, at 5.08:1.
| Hue family | Blues |
| Lightness | medium-dark (59%) |
| Chroma | moderately saturated (0.130) |
| Temperature | cool |
| Nearest name | Windows Blue (#3778BF) |
| Black text | 5.08:1 |
| White text | 4.13:1 |
Values
| HEX | #557BCB |
| RGB | rgb(85, 123, 203) |
| HSL | hsl(221, 53%, 56%) |
| OKLCH | oklch(59.2% 0.13 263.7) |
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 #557BCB | 4.13:1 | AA large text | Lc -73.7 | Content text, not long reading |
| Black text on #557BCB | 5.08:1 | AA | Lc 35.9 | Non-text elements, placeholder text |
| #557BCB text on white | 4.13:1 | AA large text | Lc 68.2 | Content text, not long reading |
| #557BCB text on black | 5.08:1 | AA | Lc -33.4 | 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
#F3F5FB
oklch(97% 0.008 271.3)
-
Step 100
100
#E4EAF6
oklch(93.6% 0.017 264.5)
-
Step 200
200
#CEDAEF
oklch(88.6% 0.032 261.7)
-
Step 300
300
#ADC1E7
oklch(80.9% 0.058 263.2)
-
Step 400
400
#82A0DC
oklch(70.7% 0.095 263.7)
-
Step 500
500
#6488D2
oklch(63.2% 0.119 263.6)
-
Step 600
600 (this color)
#557BCB
oklch(59.2% 0.13 263.7)
-
Step 700
700
#3C5DA5
oklch(49% 0.122 263.9)
-
Step 800
800
#324D86
oklch(42.8% 0.1 263.6)
-
Step 900
900
#2C406B
oklch(37.7% 0.078 264.1)
-
Step 950
950
#1A263F
oklch(27.1% 0.05 263.9)
#557BCB 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) | #5983CE | 0.023 |
| Deuteranopia (no green cones) | #4A78C9 | 0.016 |
| Tritanopia (no blue cones) | #008D99 | 0.115 |
| Achromatopsia (no color) | #7D7D7D | 0.130 |
Harmonies
Hue rotations in OKLCH that keep this color's lightness and chroma.
Complementary
The opposite hue (180°).
- #557BCB
#557BCB
oklch(59.2% 0.13 263.7)
- #A07600
#A07600
oklch(59.2% 0.122 83.6)
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 #557BCB, closest first.
Similar named colors
The eight closest entries in our named color list, with their ΔE distance.
- Windows Blue #3778BF ΔE 0.037
- Cool Blue #4984B8 ΔE 0.044
- Steel Blue #4682B4 ΔE 0.047
- Water Blue #0E87CC ΔE 0.051
- Off Blue #5684AE ΔE 0.057
- Dark Sky Blue #448EE4 ΔE 0.057
- Soft Blue #6488EA ΔE 0.059
- Dusty Blue #5A86AD ΔE 0.062
Use #557BCB 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.