#3F75D9
Closest named color: Royal Blue (#4169E1). oklch(57.8% 0.164 261.5), rgb(63, 117, 217).
Aa
Black text reads best on this color (4.75:1).
About this color
#3F75D9 is a medium-dark, vivid blue. In OKLCH its lightness is 58%, its chroma 0.164 and its hue 261°. Its hue sits on the cool side of the wheel. The nearest named color is Royal Blue (#4169E1), ΔE 0.034 away. Black text reads best on it, at 4.75:1.
| Hue family | Blues |
| Lightness | medium-dark (58%) |
| Chroma | vivid (0.164) |
| Temperature | cool |
| Nearest name | Royal Blue (#4169E1) |
| Black text | 4.75:1 |
| White text | 4.41:1 |
Values
| HEX | #3F75D9 |
| RGB | rgb(63, 117, 217) |
| HSL | hsl(219, 67%, 55%) |
| OKLCH | oklch(57.8% 0.164 261.5) |
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 #3F75D9 | 4.41:1 | AA large text | Lc -75.7 | Fine for body text |
| Black text on #3F75D9 | 4.75:1 | AA | Lc 33.8 | Non-text elements, placeholder text |
| #3F75D9 text on white | 4.41:1 | AA large text | Lc 70.2 | Content text, not long reading |
| #3F75D9 text on black | 4.75:1 | AA | Lc -31.4 | 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
#E2EAF9
oklch(93.5% 0.022 263.2)
-
Step 200
200
#CADAF5
oklch(88.5% 0.041 260.9)
-
Step 300
300
#A6C2F1
oklch(81% 0.073 260.7)
-
Step 400
400
#77A0EA
oklch(70.7% 0.118 261.7)
-
Step 500
500
#5487E4
oklch(63.2% 0.151 261.4)
-
Step 600
600 (this color)
#3F75D9
oklch(57.8% 0.164 261.5)
-
Step 700
700
#2B5CB6
oklch(49.2% 0.153 261.3)
-
Step 800
800
#254B93
oklch(42.7% 0.127 261.7)
-
Step 900
900
#224075
oklch(37.8% 0.098 260.9)
-
Step 950
950
#152645
oklch(27.2% 0.062 261.5)
#3F75D9 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) | #4180DD | 0.029 |
| Deuteranopia (no green cones) | #1E71D7 | 0.027 |
| Tritanopia (no blue cones) | #008C9C | 0.130 |
| Achromatopsia (no color) | #787878 | 0.164 |
Harmonies
Hue rotations in OKLCH that keep this color's lightness and chroma.
Complementary
The opposite hue (180°).
- #3F75D9
#3F75D9
oklch(57.8% 0.164 261.5)
- #9D7100
#9D7100
oklch(57.8% 0.119 81.4)
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 #3F75D9, closest first.
Similar named colors
The eight closest entries in our named color list, with their ΔE distance.
- Royal Blue #4169E1 ΔE 0.034
- Windows Blue #3778BF ΔE 0.043
- Cerulean Blue #056EEE ΔE 0.049
- Clear Blue #247AFD ΔE 0.055
- Water Blue #0E87CC ΔE 0.058
- Neon Blue #4361EE ΔE 0.060
- Dark Periwinkle #665FD1 ΔE 0.065
- Dark Sky Blue #448EE4 ΔE 0.068
Use #3F75D9 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.