#3F99DD
Closest named color: Chefchaouen Blue (#4895EF). oklch(66% 0.132 244.8), rgb(63, 153, 221).
Aa
Black text reads best on this color (6.81:1).
About this color
#3F99DD is a medium-light, moderately saturated blue. In OKLCH its lightness is 66%, its chroma 0.132 and its hue 245°. Its hue sits on the cool side of the wheel. The nearest named color is Chefchaouen Blue (#4895EF), ΔE 0.032 away. Black text reads best on it, at 6.81:1.
| Hue family | Blues |
| Lightness | medium-light (66%) |
| Chroma | moderately saturated (0.132) |
| Temperature | cool |
| Nearest name | Chefchaouen Blue (#4895EF) |
| Black text | 6.81:1 |
| White text | 3.08:1 |
Values
| HEX | #3F99DD |
| RGB | rgb(63, 153, 221) |
| HSL | hsl(206, 70%, 56%) |
| OKLCH | oklch(66% 0.132 244.8) |
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 #3F99DD | 3.08:1 | AA large text | Lc -62.8 | Content text, not long reading |
| Black text on #3F99DD | 6.81:1 | AA | Lc 46.6 | Large or bold text, headings |
| #3F99DD text on white | 3.08:1 | AA large text | Lc 57.4 | Large or bold text, headings |
| #3F99DD text on black | 6.81:1 | AA | Lc -44.3 | 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 500.
-
Step 50
50
#F1F6FB
oklch(97.1% 0.009 247.9)
-
Step 100
100
#E0ECF6
oklch(93.7% 0.019 243)
-
Step 200
200
#C6DCF0
oklch(88.4% 0.036 245.7)
-
Step 300
300
#9EC6E8
oklch(80.9% 0.064 244.3)
-
Step 400
400
#66A7DD
oklch(70.7% 0.104 245.1)
-
Step 500
500 (this color)
#3F99DD
oklch(66% 0.132 244.8)
-
Step 600
600
#0079BE
oklch(55.6% 0.139 244.6)
-
Step 700
700
#0065A1
oklch(49% 0.124 245.1)
-
Step 800
800
#005385
oklch(42.7% 0.107 244.8)
-
Step 900
900
#0D456C
oklch(37.7% 0.086 245)
-
Step 950
950
#0B293F
oklch(27.1% 0.054 244.1)
#3F99DD 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) | #7A9BE0 | 0.058 |
| Deuteranopia (no green cones) | #648CDC | 0.044 |
| Tritanopia (no blue cones) | #00A9B1 | 0.094 |
| Achromatopsia (no color) | #939393 | 0.132 |
Harmonies
Hue rotations in OKLCH that keep this color's lightness and chroma.
Complementary
The opposite hue (180°).
- #3F99DD
#3F99DD
oklch(66% 0.132 244.8)
- #C97F29
#C97F29
oklch(66% 0.132 64.9)
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 #3F99DD, closest first.
Similar named colors
The eight closest entries in our named color list, with their ΔE distance.
- Chefchaouen Blue #4895EF ΔE 0.032
- Dark Sky Blue #448EE4 ΔE 0.034
- Cornflower Blue #6495ED ΔE 0.043
- Faded Blue #658CBB ΔE 0.059
- Soft Blue #6488EA ΔE 0.060
- Water Blue #0E87CC ΔE 0.062
- Dodger Blue #1E90FF ΔE 0.063
- Cool Blue #4984B8 ΔE 0.071
Use #3F99DD 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.