#3F9BF0
Closest named color: Chefchaouen Blue (#4895EF). oklch(67.4% 0.153 249.7), rgb(63, 155, 240).
Aa
Black text reads best on this color (7.15:1).
About this color
#3F9BF0 is a medium-light, vivid blue. In OKLCH its lightness is 67%, its chroma 0.153 and its hue 250°. Its hue sits on the cool side of the wheel. The nearest named color is Chefchaouen Blue (#4895EF), ΔE 0.016 away. Black text reads best on it, at 7.15:1.
| Hue family | Blues |
| Lightness | medium-light (67%) |
| Chroma | vivid (0.153) |
| Temperature | cool |
| Nearest name | Chefchaouen Blue (#4895EF) |
| Black text | 7.15:1 |
| White text | 2.93:1 |
Values
| HEX | #3F9BF0 |
| RGB | rgb(63, 155, 240) |
| HSL | hsl(209, 86%, 59%) |
| OKLCH | oklch(67.4% 0.153 249.7) |
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 #3F9BF0 | 2.93:1 | Fails | Lc -60.7 | Content text, not long reading |
| Black text on #3F9BF0 | 7.15:1 | AAA | Lc 48.6 | Large or bold text, headings |
| #3F9BF0 text on white | 2.93:1 | Fails | Lc 55.4 | Large or bold text, headings |
| #3F9BF0 text on black | 7.15:1 | AAA | Lc -46.4 | 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 400.
-
Step 50
50
#EFF6FE
oklch(97% 0.013 251.6)
-
Step 100
100
#DCECFC
oklch(93.6% 0.028 248.1)
-
Step 200
200
#BFDDFC
oklch(88.6% 0.054 249.3)
-
Step 300
300
#91C6FC
oklch(81% 0.095 249.5)
-
Step 400
400 (this color)
#3F9BF0
oklch(67.4% 0.153 249.7)
-
Step 500
500
#008CEF
oklch(63% 0.178 249.9)
-
Step 600
600
#0076CA
oklch(55.7% 0.156 249.7)
-
Step 700
700
#0063AB
oklch(49.2% 0.138 249.7)
-
Step 800
800
#00518D
oklch(42.7% 0.12 249.5)
-
Step 900
900
#004377
oklch(37.7% 0.106 249.9)
-
Step 950
950
#002749
oklch(26.8% 0.076 249.9)
#3F9BF0 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) | #74A0F4 | 0.052 |
| Deuteranopia (no green cones) | #5A8FEE | 0.035 |
| Tritanopia (no blue cones) | #00AFBA | 0.113 |
| Achromatopsia (no color) | #979797 | 0.153 |
Harmonies
Hue rotations in OKLCH that keep this color's lightness and chroma.
Complementary
The opposite hue (180°).
- #3F9BF0
#3F9BF0
oklch(67.4% 0.153 249.7)
- #CF8300
#CF8300
oklch(67.4% 0.146 69.4)
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 #3F9BF0, closest first.
Similar named colors
The eight closest entries in our named color list, with their ΔE distance.
- Chefchaouen Blue #4895EF ΔE 0.016
- Cornflower Blue #6495ED ΔE 0.032
- Dark Sky Blue #448EE4 ΔE 0.036
- Dodger Blue #1E90FF ΔE 0.045
- Soft Blue #6488EA ΔE 0.054
- Water Blue #0E87CC ΔE 0.079
- Faded Blue #658CBB ΔE 0.083
- Periwinkle Blue #8F99FB ΔE 0.084
Use #3F9BF0 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.