#3F99EC
Closest named color: Chefchaouen Blue (#4895EF). oklch(66.8% 0.15 249.6), rgb(63, 153, 236).
Aa
Black text reads best on this color (6.97:1).
About this color
#3F99EC is a medium-light, vivid blue. In OKLCH its lightness is 67%, its chroma 0.150 and its hue 250°. Its hue sits on the cool side of the wheel. The nearest named color is Chefchaouen Blue (#4895EF), ΔE 0.013 away. Black text reads best on it, at 6.97:1.
| Hue family | Blues |
| Lightness | medium-light (67%) |
| Chroma | vivid (0.150) |
| Temperature | cool |
| Nearest name | Chefchaouen Blue (#4895EF) |
| Black text | 6.97:1 |
| White text | 3.00:1 |
Values
| HEX | #3F99EC |
| RGB | rgb(63, 153, 236) |
| HSL | hsl(209, 82%, 59%) |
| OKLCH | oklch(66.8% 0.15 249.6) |
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 #3F99EC | 3.00:1 | AA large text | Lc -61.8 | Content text, not long reading |
| Black text on #3F99EC | 6.97:1 | AA | Lc 47.6 | Large or bold text, headings |
| #3F99EC text on white | 3.00:1 | AA large text | Lc 56.4 | Large or bold text, headings |
| #3F99EC text on black | 6.97:1 | AA | Lc -45.3 | Large or bold text, headings |
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
#E0EBF8
oklch(93.6% 0.021 252.5)
-
Step 200
200
#C5DCF4
oklch(88.5% 0.041 249.4)
-
Step 300
300
#9DC5EF
oklch(80.9% 0.073 250)
-
Step 400
400
#64A6E7
oklch(70.8% 0.117 249.5)
-
Step 500
500 (this color)
#3F99EC
oklch(66.8% 0.15 249.6)
-
Step 600
600
#0076CA
oklch(55.7% 0.156 249.7)
-
Step 700
700
#0063AA
oklch(49.1% 0.137 249.4)
-
Step 800
800
#00518D
oklch(42.7% 0.12 249.5)
-
Step 900
900
#0B4373
oklch(37.6% 0.099 250.1)
-
Step 950
950
#0A2843
oklch(27% 0.061 249.3)
#3F99EC 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) | #739DEF | 0.050 |
| Deuteranopia (no green cones) | #5A8DEA | 0.035 |
| Tritanopia (no blue cones) | #00ADB7 | 0.112 |
| Achromatopsia (no color) | #959595 | 0.150 |
Harmonies
Hue rotations in OKLCH that keep this color's lightness and chroma.
Complementary
The opposite hue (180°).
- #3F99EC
#3F99EC
oklch(66.8% 0.15 249.6)
- #CC8200
#CC8200
oklch(66.8% 0.145 70)
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 #3F99EC, closest first.
Similar named colors
The eight closest entries in our named color list, with their ΔE distance.
- Chefchaouen Blue #4895EF ΔE 0.013
- Dark Sky Blue #448EE4 ΔE 0.029
- Cornflower Blue #6495ED ΔE 0.032
- Dodger Blue #1E90FF ΔE 0.044
- Soft Blue #6488EA ΔE 0.050
- Water Blue #0E87CC ΔE 0.072
- Faded Blue #658CBB ΔE 0.077
- Perrywinkle #8F8CE7 ΔE 0.086
Use #3F99EC 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.