#3573B3
Closest named color: Flat Blue (#3C73A8). oklch(54.6% 0.119 251.5), rgb(53, 115, 179).
Aa
White text reads best on this color (4.93:1).
About this color
#3573B3 is a medium-dark, moderately saturated blue. In OKLCH its lightness is 55%, its chroma 0.119 and its hue 252°. Its hue sits on the cool side of the wheel. The nearest named color is Flat Blue (#3C73A8), ΔE 0.018 away. White text reads best on it, at 4.93:1.
| Hue family | Blues |
| Lightness | medium-dark (55%) |
| Chroma | moderately saturated (0.119) |
| Temperature | cool |
| Nearest name | Flat Blue (#3C73A8) |
| Black text | 4.25:1 |
| White text | 4.93:1 |
Values
| HEX | #3573B3 |
| RGB | rgb(53, 115, 179) |
| HSL | hsl(210, 54%, 45%) |
| OKLCH | oklch(54.6% 0.119 251.5) |
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 #3573B3 | 4.93:1 | AA | Lc -79.3 | Fine for body text |
| Black text on #3573B3 | 4.25:1 | AA large text | Lc 30.2 | Non-text elements, placeholder text |
| #3573B3 text on white | 4.93:1 | AA | Lc 73.9 | Content text, not long reading |
| #3573B3 text on black | 4.25:1 | AA large text | Lc -27.8 | 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
#F2F6FA
oklch(97.1% 0.007 247.9)
-
Step 100
100
#E3EBF4
oklch(93.7% 0.015 251.2)
-
Step 200
200
#CBDBED
oklch(88.5% 0.03 251.3)
-
Step 300
300
#A8C4E3
oklch(81% 0.053 251.1)
-
Step 400
400
#79A4D5
oklch(70.6% 0.086 252.2)
-
Step 500
500
#558DCA
oklch(63.1% 0.11 251.8)
-
Step 600
600 (this color)
#3573B3
oklch(54.6% 0.119 251.5)
-
Step 700
700
#2A639D
oklch(49.1% 0.111 251.4)
-
Step 800
800
#24517F
oklch(42.7% 0.091 251.2)
-
Step 900
900
#234366
oklch(37.6% 0.071 252.1)
-
Step 950
950
#15283C
oklch(27.1% 0.045 250.9)
#3573B3 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) | #5677B6 | 0.037 |
| Deuteranopia (no green cones) | #446BB2 | 0.024 |
| Tritanopia (no blue cones) | #00828A | 0.092 |
| Achromatopsia (no color) | #707070 | 0.119 |
Harmonies
Hue rotations in OKLCH that keep this color's lightness and chroma.
Complementary
The opposite hue (180°).
- #3573B3
#3573B3
oklch(54.6% 0.119 251.5)
- #9A6300
#9A6300
oklch(54.6% 0.117 71.7)
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 #3573B3, closest first.
Similar named colors
The eight closest entries in our named color list, with their ΔE distance.
- Flat Blue #3C73A8 ΔE 0.018
- Windows Blue #3778BF ΔE 0.022
- French Blue #436BAD ΔE 0.024
- Nice Blue #107AB0 ΔE 0.027
- Mid Blue #276AB3 ΔE 0.030
- Muted Blue #3B719F ΔE 0.031
- Dull Blue #49759C ΔE 0.042
- Ocean Blue #03719C ΔE 0.046
Use #3573B3 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.