#3F8BBB
Closest named color: Cool Blue (#4984B8). oklch(61% 0.104 239.4), rgb(63, 139, 187).
Aa
Black text reads best on this color (5.62:1).
About this color
#3F8BBB is a medium-dark, moderately saturated blue. In OKLCH its lightness is 61%, its chroma 0.104 and its hue 239°. Its hue sits on the cool side of the wheel. The nearest named color is Cool Blue (#4984B8), ΔE 0.020 away. Black text reads best on it, at 5.62:1.
| Hue family | Blues |
| Lightness | medium-dark (61%) |
| Chroma | moderately saturated (0.104) |
| Temperature | cool |
| Nearest name | Cool Blue (#4984B8) |
| Black text | 5.62:1 |
| White text | 3.73:1 |
Values
| HEX | #3F8BBB |
| RGB | rgb(63, 139, 187) |
| HSL | hsl(203, 50%, 49%) |
| OKLCH | oklch(61% 0.104 239.4) |
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 #3F8BBB | 3.73:1 | AA large text | Lc -70.2 | Content text, not long reading |
| Black text on #3F8BBB | 5.62:1 | AA | Lc 39.4 | Non-text elements, placeholder text |
| #3F8BBB text on white | 3.73:1 | AA large text | Lc 64.7 | Content text, not long reading |
| #3F8BBB text on black | 5.62:1 | AA | Lc -37.0 | 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
#F1F6FA
oklch(97.1% 0.008 241.7)
-
Step 100
100
#E1EBF3
oklch(93.5% 0.015 241.8)
-
Step 200
200
#C9DCEA
oklch(88.5% 0.028 239.7)
-
Step 300
300
#A3C6DF
oklch(80.9% 0.052 239.4)
-
Step 400
400
#70A8CE
oklch(70.7% 0.081 239.1)
-
Step 500
500 (this color)
#3F8BBB
oklch(61% 0.104 239.4)
-
Step 600
600
#217BAE
oklch(55.6% 0.113 239.3)
-
Step 700
700
#106796
oklch(49% 0.106 239.8)
-
Step 800
800
#13547A
oklch(42.6% 0.088 240.2)
-
Step 900
900
#194662
oklch(37.7% 0.068 239.6)
-
Step 950
950
#102939
oklch(26.9% 0.043 239.2)
#3F8BBB 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) | #758BBD | 0.057 |
| Deuteranopia (no green cones) | #647FBA | 0.046 |
| Tritanopia (no blue cones) | #00979B | 0.074 |
| Achromatopsia (no color) | #848484 | 0.105 |
Harmonies
Hue rotations in OKLCH that keep this color's lightness and chroma.
Complementary
The opposite hue (180°).
- #3F8BBB
#3F8BBB
oklch(61% 0.104 239.4)
- #B1733E
#B1733E
oklch(61% 0.104 59.4)
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 #3F8BBB, closest first.
Similar named colors
The eight closest entries in our named color list, with their ΔE distance.
- Cool Blue #4984B8 ΔE 0.020
- Steel Blue #4682B4 ΔE 0.025
- Off Blue #5684AE ΔE 0.029
- Blue NCS #118AB2 ΔE 0.029
- Dusty Blue #5A86AD ΔE 0.030
- Faded Blue #658CBB ΔE 0.037
- Water Blue #0E87CC ΔE 0.038
- Teal Blue #01889F ΔE 0.054
Use #3F8BBB 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.