#3781D3
Closest named color: Water Blue (#0E87CC). oklch(59.7% 0.145 253.4), rgb(55, 129, 211).
Aa
Black text reads best on this color (5.24:1).
About this color
#3781D3 is a medium-dark, vivid blue. In OKLCH its lightness is 60%, its chroma 0.145 and its hue 253°. Its hue sits on the cool side of the wheel. The nearest named color is Water Blue (#0E87CC), ΔE 0.027 away. Black text reads best on it, at 5.24:1.
| Hue family | Blues |
| Lightness | medium-dark (60%) |
| Chroma | vivid (0.145) |
| Temperature | cool |
| Nearest name | Water Blue (#0E87CC) |
| Black text | 5.24:1 |
| White text | 4.00:1 |
Values
| HEX | #3781D3 |
| RGB | rgb(55, 129, 211) |
| HSL | hsl(212, 64%, 52%) |
| OKLCH | oklch(59.7% 0.145 253.4) |
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 #3781D3 | 4.00:1 | AA large text | Lc -72.5 | Content text, not long reading |
| Black text on #3781D3 | 5.24:1 | AA | Lc 37.1 | Non-text elements, placeholder text |
| #3781D3 text on white | 4.00:1 | AA large text | Lc 67.0 | Content text, not long reading |
| #3781D3 text on black | 5.24:1 | AA | Lc -34.7 | 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 500.
-
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
#C7DBF3
oklch(88.4% 0.04 253)
-
Step 300
300
#A1C4EE
oklch(80.9% 0.071 253.2)
-
Step 400
400
#6CA4E6
oklch(70.7% 0.114 253.3)
-
Step 500
500 (this color)
#3781D3
oklch(59.7% 0.145 253.4)
-
Step 600
600
#1D74CC
oklch(55.7% 0.157 253.2)
-
Step 700
700
#0C61B1
oklch(49.2% 0.147 253.2)
-
Step 800
800
#104F8F
oklch(42.7% 0.122 253.4)
-
Step 900
900
#174272
oklch(37.6% 0.095 253.7)
-
Step 950
950
#0F2743
oklch(27% 0.06 253.9)
#3781D3 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) | #5B87D6 | 0.039 |
| Deuteranopia (no green cones) | #4278D1 | 0.024 |
| Tritanopia (no blue cones) | #0094A0 | 0.109 |
| Achromatopsia (no color) | #7F7F7F | 0.145 |
Harmonies
Hue rotations in OKLCH that keep this color's lightness and chroma.
Complementary
The opposite hue (180°).
- #3781D3
#3781D3
oklch(59.7% 0.145 253.4)
- #AC7100
#AC7100
oklch(59.6% 0.127 73.1)
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 #3781D3, closest first.
Similar named colors
The eight closest entries in our named color list, with their ΔE distance.
- Water Blue #0E87CC ΔE 0.027
- Windows Blue #3778BF ΔE 0.036
- Dark Sky Blue #448EE4 ΔE 0.044
- Cool Blue #4984B8 ΔE 0.046
- Steel Blue #4682B4 ΔE 0.049
- Soft Blue #6488EA ΔE 0.061
- Nice Blue #107AB0 ΔE 0.061
- Off Blue #5684AE ΔE 0.064
Use #3781D3 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.