#3777D0
Closest named color: Windows Blue (#3778BF). oklch(57.3% 0.152 257.3), rgb(55, 119, 208).
Aa
Black text reads best on this color (4.71:1).
About this color
#3777D0 is a medium-dark, vivid blue. In OKLCH its lightness is 57%, its chroma 0.152 and its hue 257°. Its hue sits on the cool side of the wheel. The nearest named color is Windows Blue (#3778BF), ΔE 0.027 away. Black text reads best on it, at 4.71:1.
| Hue family | Blues |
| Lightness | medium-dark (57%) |
| Chroma | vivid (0.152) |
| Temperature | cool |
| Nearest name | Windows Blue (#3778BF) |
| Black text | 4.71:1 |
| White text | 4.45:1 |
Values
| HEX | #3777D0 |
| RGB | rgb(55, 119, 208) |
| HSL | hsl(215, 62%, 52%) |
| OKLCH | oklch(57.3% 0.152 257.3) |
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 #3777D0 | 4.45:1 | AA large text | Lc -76.0 | Fine for body text |
| Black text on #3777D0 | 4.71:1 | AA | Lc 33.5 | Non-text elements, placeholder text |
| #3777D0 text on white | 4.45:1 | AA large text | Lc 70.6 | Content text, not long reading |
| #3777D0 text on black | 4.71:1 | AA | Lc -31.1 | 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
#F2F6FC
oklch(97.2% 0.009 258.3)
-
Step 100
100
#E2EBF7
oklch(93.7% 0.019 255.5)
-
Step 200
200
#CADBF3
oklch(88.6% 0.038 257)
-
Step 300
300
#A5C3ED
oklch(81% 0.068 256.8)
-
Step 400
400
#74A2E4
oklch(70.6% 0.109 257.4)
-
Step 500
500
#4F8ADD
oklch(63.2% 0.14 257.2)
-
Step 600
600 (this color)
#3777D0
oklch(57.3% 0.152 257.3)
-
Step 700
700
#245FAF
oklch(49.1% 0.141 257.2)
-
Step 800
800
#204E8E
oklch(42.8% 0.117 257.4)
-
Step 900
900
#1F4171
oklch(37.6% 0.092 257.4)
-
Step 950
950
#132742
oklch(27.1% 0.057 256.4)
#3777D0 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) | #4B7FD3 | 0.030 |
| Deuteranopia (no green cones) | #3071CE | 0.018 |
| Tritanopia (no blue cones) | #008C99 | 0.119 |
| Achromatopsia (no color) | #777777 | 0.152 |
Harmonies
Hue rotations in OKLCH that keep this color's lightness and chroma.
Complementary
The opposite hue (180°).
- #3777D0
#3777D0
oklch(57.3% 0.152 257.3)
- #9F6D00
#9F6D00
oklch(57.2% 0.12 77)
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 #3777D0, closest first.
Similar named colors
The eight closest entries in our named color list, with their ΔE distance.
- Windows Blue #3778BF ΔE 0.027
- Water Blue #0E87CC ΔE 0.046
- Royal Blue #4169E1 ΔE 0.047
- Mid Blue #276AB3 ΔE 0.057
- Nice Blue #107AB0 ΔE 0.058
- French Blue #436BAD ΔE 0.058
- Cerulean Blue #056EEE ΔE 0.059
- Cool Blue #4984B8 ΔE 0.060
Use #3777D0 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.