Flat Blue #3C73A8
Flat Blue is a medium-dark, moderately saturated blue with hex code #3C73A8 and RGB rgb(60, 115, 168).
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White text reads best on this color (4.98:1).
About this color
#3C73A8 is a medium-dark, moderately saturated blue. In OKLCH its lightness is 54%, its chroma 0.102 and its hue 249°. Its hue sits on the cool side of the wheel. It is the named color Flat Blue. White text reads best on it, at 4.98:1.
| Hue family | Blues |
| Lightness | medium-dark (54%) |
| Chroma | moderately saturated (0.102) |
| Temperature | cool |
| Nearest name | Flat Blue |
| Black text | 4.20:1 |
| White text | 4.98:1 |
Colors that go with Flat Blue
Matches found by rotating Flat Blue around the OKLCH hue wheel, each labelled with the closest name in our list.
Complementary
The opposite hue (180°).
Analogous
Neighbouring hues, 30° either side.
Triadic
Three hues spaced 120° apart.
Color palettes with Flat Blue
Curated color palettes that contain a color within ΔE 0.06 (OKLab) of Flat Blue, closest first.
Similar named colors
The eight named colors closest to Flat Blue, with their ΔE distance.
- Muted Blue #3B719F ΔE 0.014
- Dull Blue #49759C ΔE 0.024
- French Blue #436BAD ΔE 0.026
- Nice Blue #107AB0 ΔE 0.029
- Cerulean #457B9D ΔE 0.034
- Windows Blue #3778BF ΔE 0.036
- Ocean Blue #03719C ΔE 0.038
- Mid Blue #276AB3 ΔE 0.039
More about Flat Blue
How to make Flat Blue
A starting recipe from common paint colors, found with a spectral paint model (the color mixer’s paint mode). Real pigments vary, so mix a small test batch and adjust.
- 4 parts blue
- 3 parts pink
- 1 part green
Recipe result: #3A71AA, a difference of ΔE 0.007 from Flat Blue. That is very close: most people will not see the difference.
Codes for Flat Blue in every format
| HEX | #3C73A8 |
| RGB | rgb(60, 115, 168) |
| HSL | hsl(209, 47%, 45%) |
| OKLCH | oklch(54.2% 0.102 249.4) |
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 #3C73A8 | 4.98:1 | AA | Lc -79.7 | Fine for body text |
| Black text on #3C73A8 | 4.20:1 | AA large text | Lc 29.8 | Dividers and decoration only |
| #3C73A8 text on white | 4.98:1 | AA | Lc 74.3 | Content text, not long reading |
| #3C73A8 text on black | 4.20:1 | AA large text | Lc -27.4 | Dividers and decoration only |
Shades and tints of Flat Blue
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
#F2F6F9
oklch(97.1% 0.006 239.8)
-
Step 100
100
#E3EBF3
oklch(93.6% 0.014 248)
-
Step 200
200
#CDDBEA
oklch(88.5% 0.026 250)
-
Step 300
300
#ABC4DE
oklch(81% 0.046 249.4)
-
Step 400
400
#7DA5CD
oklch(70.8% 0.073 248.9)
-
Step 500
500
#5B8EC0
oklch(63.2% 0.094 249)
-
Step 600
600 (this color)
#3C73A8
oklch(54.2% 0.102 249.4)
-
Step 700
700
#326494
oklch(49.1% 0.094 249.5)
-
Step 800
800
#2A5278
oklch(42.8% 0.078 249)
-
Step 900
900
#274461
oklch(37.8% 0.061 249.7)
-
Step 950
950
#172839
oklch(27.1% 0.039 249.5)
Flat Blue 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) | #5C75AA | 0.037 |
| Deuteranopia (no green cones) | #4D6BA7 | 0.026 |
| Tritanopia (no blue cones) | #007F86 | 0.079 |
| Achromatopsia (no color) | #707070 | 0.102 |
Use Flat Blue 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.