#3370A8
Closest named color: Flat Blue (#3C73A8). oklch(53.2% 0.109 248.9), rgb(51, 112, 168).
Aa
White text reads best on this color (5.21:1).
About this color
#3370A8 is a medium-dark, moderately saturated blue. In OKLCH its lightness is 53%, its chroma 0.109 and its hue 249°. Its hue sits on the cool side of the wheel. The nearest named color is Flat Blue (#3C73A8), ΔE 0.013 away. White text reads best on it, at 5.21:1.
| Hue family | Blues |
| Lightness | medium-dark (53%) |
| Chroma | moderately saturated (0.109) |
| Temperature | cool |
| Nearest name | Flat Blue (#3C73A8) |
| Black text | 4.02:1 |
| White text | 5.21:1 |
Values
| HEX | #3370A8 |
| RGB | rgb(51, 112, 168) |
| HSL | hsl(209, 53%, 43%) |
| OKLCH | oklch(53.2% 0.109 248.9) |
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 #3370A8 | 5.21:1 | AA | Lc -81.0 | Fine for body text |
| Black text on #3370A8 | 4.02:1 | AA large text | Lc 28.4 | Dividers and decoration only |
| #3370A8 text on white | 5.21:1 | AA | Lc 75.6 | Fine for body text |
| #3370A8 text on black | 4.02:1 | AA large text | Lc -26.1 | 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
#E3EBF3
oklch(93.6% 0.014 248)
-
Step 200
200
#CCDBEB
oklch(88.5% 0.027 249.9)
-
Step 300
300
#A9C4DF
oklch(80.9% 0.048 248.4)
-
Step 400
400
#7AA5D0
oklch(70.7% 0.079 249)
-
Step 500
500
#578EC3
oklch(63.1% 0.099 248.8)
-
Step 600
600 (this color)
#3370A8
oklch(53.2% 0.109 248.9)
-
Step 700
700
#2C6497
oklch(49.1% 0.101 248.8)
-
Step 800
800
#26527B
oklch(42.8% 0.084 249)
-
Step 900
900
#244463
oklch(37.7% 0.066 249.2)
-
Step 950
950
#16283A
oklch(27.1% 0.041 249.6)
#3370A8 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) | #5773AA | 0.040 |
| Deuteranopia (no green cones) | #4767A7 | 0.029 |
| Tritanopia (no blue cones) | #007D84 | 0.082 |
| Achromatopsia (no color) | #6C6C6C | 0.109 |
Harmonies
Hue rotations in OKLCH that keep this color's lightness and chroma.
Complementary
The opposite hue (180°).
- #3370A8
#3370A8
oklch(53.2% 0.109 248.9)
- #945F14
#945F14
oklch(53.1% 0.108 69.1)
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 #3370A8, closest first.
Similar named colors
The eight closest entries in our named color list, with their ΔE distance.
- Flat Blue #3C73A8 ΔE 0.013
- Muted Blue #3B719F ΔE 0.016
- French Blue #436BAD ΔE 0.022
- Mid Blue #276AB3 ΔE 0.029
- Nice Blue #107AB0 ΔE 0.030
- Ocean Blue #03719C ΔE 0.031
- Dull Blue #49759C ΔE 0.034
- Windows Blue #3778BF ΔE 0.040
Use #3370A8 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.