#3F73E7
Closest named color: Royal Blue (#4169E1). oklch(58.3% 0.185 263.5), rgb(63, 115, 231).
Aa
Black text reads best on this color (4.81:1).
About this color
#3F73E7 is a medium-dark, vivid blue. In OKLCH its lightness is 58%, its chroma 0.185 and its hue 264°. Its hue sits on the cool side of the wheel. The nearest named color is Royal Blue (#4169E1), ΔE 0.025 away. Black text reads best on it, at 4.81:1.
| Hue family | Blues |
| Lightness | medium-dark (58%) |
| Chroma | vivid (0.185) |
| Temperature | cool |
| Nearest name | Royal Blue (#4169E1) |
| Black text | 4.81:1 |
| White text | 4.35:1 |
Values
| HEX | #3F73E7 |
| RGB | rgb(63, 115, 231) |
| HSL | hsl(221, 78%, 58%) |
| OKLCH | oklch(58.3% 0.185 263.5) |
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 #3F73E7 | 4.35:1 | AA large text | Lc -75.2 | Fine for body text |
| Black text on #3F73E7 | 4.81:1 | AA | Lc 34.3 | Non-text elements, placeholder text |
| #3F73E7 text on white | 4.35:1 | AA large text | Lc 69.8 | Content text, not long reading |
| #3F73E7 text on black | 4.81:1 | AA | Lc -31.9 | 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
#F2F6FD
oklch(97.2% 0.01 261.8)
-
Step 100
100
#E2EAFB
oklch(93.6% 0.025 265.6)
-
Step 200
200
#CADAF9
oklch(88.6% 0.046 263.7)
-
Step 300
300
#A5C1F7
oklch(80.9% 0.083 263.3)
-
Step 400
400
#759FF3
oklch(70.8% 0.132 263.2)
-
Step 500
500
#5284EF
oklch(63.2% 0.17 263.5)
-
Step 600
600 (this color)
#3F73E7
oklch(58.3% 0.185 263.5)
-
Step 700
700
#2A58C0
oklch(49.1% 0.171 263.4)
-
Step 800
800
#24489C
oklch(42.6% 0.143 263.9)
-
Step 900
900
#213E7C
oklch(37.8% 0.111 263.2)
-
Step 950
950
#142548
oklch(27.1% 0.069 263.1)
#3F73E7 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) | #2B81EB | 0.035 |
| Deuteranopia (no green cones) | #0072E5 | 0.031 |
| Tritanopia (no blue cones) | #008FA2 | 0.147 |
| Achromatopsia (no color) | #797979 | 0.185 |
Harmonies
Hue rotations in OKLCH that keep this color's lightness and chroma.
Complementary
The opposite hue (180°).
- #3F73E7
#3F73E7
oklch(58.3% 0.185 263.5)
- #9D7400
#9D7400
oklch(58.4% 0.12 83.8)
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 #3F73E7, closest first.
Similar named colors
The eight closest entries in our named color list, with their ΔE distance.
- Royal Blue #4169E1 ΔE 0.025
- Cerulean Blue #056EEE ΔE 0.036
- Clear Blue #247AFD ΔE 0.037
- Neon Blue #4361EE ΔE 0.044
- Cornflower #6A79F7 ΔE 0.058
- Bright Blue #0165FC ΔE 0.060
- Azul #1D5DEC ΔE 0.064
- Windows Blue #3778BF ΔE 0.066
Use #3F73E7 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.