#3748BB
Closest named color: Blue Blue (#2242C7). oklch(46.1% 0.181 271), rgb(55, 72, 187).
Aa
White text reads best on this color (7.48:1).
About this color
#3748BB is a medium-dark, vivid blue. In OKLCH its lightness is 46%, its chroma 0.181 and its hue 271°. Its hue sits on the cool side of the wheel. The nearest named color is Blue Blue (#2242C7), ΔE 0.033 away. White text reads best on it, at 7.48:1.
| Hue family | Blues |
| Lightness | medium-dark (46%) |
| Chroma | vivid (0.181) |
| Temperature | cool |
| Nearest name | Blue Blue (#2242C7) |
| Black text | 2.80:1 |
| White text | 7.48:1 |
Values
| HEX | #3748BB |
| RGB | rgb(55, 72, 187) |
| HSL | hsl(232, 55%, 47%) |
| OKLCH | oklch(46.1% 0.181 271) |
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 #3748BB | 7.48:1 | AAA | Lc -90.3 | Preferred for body text |
| Black text on #3748BB | 2.80:1 | Fails | Lc 18.6 | Dividers and decoration only |
| #3748BB text on white | 7.48:1 | AAA | Lc 85.5 | Fine for body text |
| #3748BB text on black | 2.80:1 | Fails | Lc -16.6 | 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 700.
-
Step 50
50
#F2F5FE
oklch(97% 0.012 271.3)
-
Step 100
100
#E3E9FB
oklch(93.5% 0.025 271.1)
-
Step 200
200
#CDD8FA
oklch(88.5% 0.048 271.2)
-
Step 300
300
#ABBEFA
oklch(80.9% 0.088 270.8)
-
Step 400
400
#819AF7
oklch(70.7% 0.139 271.1)
-
Step 500
500
#637EF4
oklch(63.2% 0.178 270.8)
-
Step 600
600
#4C63E3
oklch(55.5% 0.195 270.9)
-
Step 700
700 (this color)
#3748BB
oklch(46.1% 0.181 271)
-
Step 800
800
#33439F
oklch(42.6% 0.15 271.1)
-
Step 900
900
#2C3A7E
oklch(37.7% 0.116 271.1)
-
Step 950
950
#1A234A
oklch(27.1% 0.073 271.1)
#3748BB 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) | #005BBF | 0.051 |
| Deuteranopia (no green cones) | #004FB9 | 0.037 |
| Tritanopia (no blue cones) | #00657A | 0.145 |
| Achromatopsia (no color) | #555555 | 0.181 |
Harmonies
Hue rotations in OKLCH that keep this color's lightness and chroma.
Complementary
The opposite hue (180°).
- #3748BB
#3748BB
oklch(46.1% 0.181 271)
- #6C5600
#6C5600
oklch(46.2% 0.095 91.5)
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 #3748BB, closest first.
Similar named colors
The eight closest entries in our named color list, with their ΔE distance.
- Blue Blue #2242C7 ΔE 0.033
- Majorelle Blue #3F37C9 ΔE 0.040
- Blue With A Hint Of Purple #533CC6 ΔE 0.047
- Blurple #5539CC ΔE 0.055
- Sapphire #2138AB ΔE 0.055
- Blueberry #464196 ΔE 0.063
- Bluey Purple #6241C7 ΔE 0.066
- Warm Blue #4B57DB ΔE 0.068
Use #3748BB 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.