#2171CF
Closest named color: Windows Blue (#3778BF). oklch(55.3% 0.164 255.5), rgb(33, 113, 207).
Aa
White text reads best on this color (4.85:1).
About this color
#2171CF is a medium-dark, vivid blue. In OKLCH its lightness is 55%, its chroma 0.164 and its hue 256°. Its hue sits on the cool side of the wheel. The nearest named color is Windows Blue (#3778BF), ΔE 0.037 away. White text reads best on it, at 4.85:1.
| Hue family | Blues |
| Lightness | medium-dark (55%) |
| Chroma | vivid (0.164) |
| Temperature | cool |
| Nearest name | Windows Blue (#3778BF) |
| Black text | 4.32:1 |
| White text | 4.85:1 |
Values
| HEX | #2171CF |
| RGB | rgb(33, 113, 207) |
| HSL | hsl(212, 73%, 47%) |
| OKLCH | oklch(55.3% 0.164 255.5) |
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 #2171CF | 4.85:1 | AA | Lc -78.6 | Fine for body text |
| Black text on #2171CF | 4.32:1 | AA large text | Lc 31.0 | Non-text elements, placeholder text |
| #2171CF text on white | 4.85:1 | AA | Lc 73.1 | Content text, not long reading |
| #2171CF text on black | 4.32:1 | AA large text | Lc -28.6 | 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
#F1F6FC
oklch(97.1% 0.01 252.8)
-
Step 100
100
#E1EBF8
oklch(93.6% 0.021 254.9)
-
Step 200
200
#C8DBF4
oklch(88.5% 0.04 255.3)
-
Step 300
300
#A1C3F0
oklch(80.8% 0.074 255.6)
-
Step 400
400
#6DA3E9
oklch(70.7% 0.118 255.4)
-
Step 500
500
#458AE2
oklch(63.1% 0.15 255.7)
-
Step 600
600 (this color)
#2171CF
oklch(55.3% 0.164 255.5)
-
Step 700
700
#145FB4
oklch(49.1% 0.152 255.5)
-
Step 800
800
#144E92
oklch(42.7% 0.126 255.5)
-
Step 900
900
#194174
oklch(37.6% 0.098 256)
-
Step 950
950
#102744
oklch(27.1% 0.062 255.3)
#2171CF 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) | #3E7AD3 | 0.035 |
| Deuteranopia (no green cones) | #116ACD | 0.021 |
| Tritanopia (no blue cones) | #008896 | 0.124 |
| Achromatopsia (no color) | #717171 | 0.164 |
Harmonies
Hue rotations in OKLCH that keep this color's lightness and chroma.
Complementary
The opposite hue (180°).
- #2171CF
#2171CF
oklch(55.3% 0.164 255.5)
- #996700
#996700
oklch(55.3% 0.116 75.6)
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 #2171CF, closest first.
Similar named colors
The eight closest entries in our named color list, with their ΔE distance.
- Windows Blue #3778BF ΔE 0.037
- Royal Blue #4169E1 ΔE 0.042
- Mid Blue #276AB3 ΔE 0.045
- Cerulean Blue #056EEE ΔE 0.049
- French Blue #436BAD ΔE 0.056
- Nice Blue #107AB0 ΔE 0.059
- Water Blue #0E87CC ΔE 0.061
- Flat Blue #3C73A8 ΔE 0.064
Use #2171CF 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.