#3781BD
Closest named color: Steel Blue (#4682B4). oklch(58.5% 0.118 246.3), rgb(55, 129, 189).
Aa
Black text reads best on this color (5.03:1).
About this color
#3781BD is a medium-dark, moderately saturated blue. In OKLCH its lightness is 58%, its chroma 0.118 and its hue 246°. Its hue sits on the cool side of the wheel. The nearest named color is Steel Blue (#4682B4), ΔE 0.019 away. Black text reads best on it, at 5.03:1.
| Hue family | Blues |
| Lightness | medium-dark (58%) |
| Chroma | moderately saturated (0.118) |
| Temperature | cool |
| Nearest name | Steel Blue (#4682B4) |
| Black text | 5.03:1 |
| White text | 4.16:1 |
Values
| HEX | #3781BD |
| RGB | rgb(55, 129, 189) |
| HSL | hsl(207, 55%, 48%) |
| OKLCH | oklch(58.5% 0.118 246.3) |
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 #3781BD | 4.16:1 | AA large text | Lc -73.9 | Content text, not long reading |
| Black text on #3781BD | 5.03:1 | AA | Lc 35.7 | Non-text elements, placeholder text |
| #3781BD text on white | 4.16:1 | AA large text | Lc 68.4 | Content text, not long reading |
| #3781BD text on black | 5.03:1 | AA | Lc -33.2 | 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
#F2F6FA
oklch(97.1% 0.007 247.9)
-
Step 100
100
#E2EBF4
oklch(93.6% 0.016 248)
-
Step 200
200
#CADCEC
oklch(88.6% 0.029 244.9)
-
Step 300
300
#A5C5E1
oklch(80.9% 0.053 244.9)
-
Step 400
400
#74A6D3
oklch(70.7% 0.085 246.5)
-
Step 500
500
#4D8FC7
oklch(63.1% 0.108 246.2)
-
Step 600
600 (this color)
#3781BD
oklch(58.5% 0.118 246.3)
-
Step 700
700
#1F659B
oklch(49.1% 0.11 246.4)
-
Step 800
800
#1D537D
oklch(42.8% 0.09 245.8)
-
Step 900
900
#1E4565
oklch(37.8% 0.071 245.9)
-
Step 950
950
#13283B
oklch(26.9% 0.045 247.5)
#3781BD 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) | #6683C0 | 0.048 |
| Deuteranopia (no green cones) | #5376BC | 0.037 |
| Tritanopia (no blue cones) | #008F96 | 0.086 |
| Achromatopsia (no color) | #7C7C7C | 0.118 |
Harmonies
Hue rotations in OKLCH that keep this color's lightness and chroma.
Complementary
The opposite hue (180°).
- #3781BD
#3781BD
oklch(58.5% 0.118 246.3)
- #AA6C1F
#AA6C1F
oklch(58.5% 0.118 66.5)
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 #3781BD, closest first.
Similar named colors
The eight closest entries in our named color list, with their ΔE distance.
- Steel Blue #4682B4 ΔE 0.019
- Cool Blue #4984B8 ΔE 0.020
- Windows Blue #3778BF ΔE 0.027
- Water Blue #0E87CC ΔE 0.028
- Nice Blue #107AB0 ΔE 0.036
- Blue NCS #118AB2 ΔE 0.038
- Off Blue #5684AE ΔE 0.038
- Dusty Blue #5A86AD ΔE 0.045
Use #3781BD 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.