Hex transparency in colors [duplicate]

Answer 1

Here's a correct table of percentages to hex values. E.g. for 50% white you'd use #80FFFFFF.

• 100% — FF
• 95% — F2
• 90% — E6
• 85% — D9
• 80% — CC
• 75% — BF
• 70% — B3
• 65% — A6
• 60% — 99
• 55% — 8C
• 50% — 80
• 45% — 73
• 40% — 66
• 35% — 59
• 30% — 4D
• 25% — 40
• 20% — 33
• 15% — 26
• 10% — 1A
• 5% — 0D
• 0% — 00

(source)

Answer 2

Using python to calculate this, for example(written in python 3), 50% transparency :

hex(round(256*0.50))

:)

Answer 3

I always keep coming here to check for int/hex alpha value. So, end up creating a simple method in my java utils class. This method will convert the percentage to hex value and append to the color code string value.

 public static String setColorAlpha(int percentage, String colorCode){
    double decValue = ((double)percentage / 100) * 255;
    String rawHexColor = colorCode.replace("#","");
    StringBuilder str = new StringBuilder(rawHexColor);

    if(Integer.toHexString((int)decValue).length() == 1)
        str.insert(0, "#0" + Integer.toHexString((int)decValue));
    else
        str.insert(0, "#" + Integer.toHexString((int)decValue));
    return str.toString();
}

So, Utils.setColorAlpha(30, "#000000") will give you #4c000000

Answer 4

I realize this is an old question, but I came across it when doing something similar.

Using SASS, you have a very elegant way to convert RGBA to hex ARGB: ie-hex-str. I've used it here in a mixin.

@mixin ie8-rgba ($r, $g, $b, $a){
    $rgba: rgba($r, $g, $b, $a);
    $ie8-rgba: ie-hex-str($rgba);
    .lt-ie9 &{
      background-color: transparent;
      filter:progid:DXImageTransform.Microsoft.gradient(GradientType=0,startColorstr='#{$ie8-rgba}', endColorstr='#{$ie8-rgba}');
  }
}

.transparent{
    @include ie8-rgba(88,153,131,.8);
    background-color: rgba(88,153,131,.8);
}

outputs:

.transparent {
  background-color: rgba(88, 153, 131, 0.8);
}
.lt-ie9 .transparent {
  background-color: transparent;
  filter: progid:DXImageTransform.Microsoft.gradient(GradientType=0,startColorstr='#CC589983', endColorstr='#CC589983');
  zoom: 1;
}

Answer 5

try this on google search (or click here)

255 * .2 to hex

it will generate 0x33 as a result.

However, google does not round off values so you can only use 1-digit multipliers. if you want to use say .85, you have to get the rounded-off value of 255 * .85 first, then type (rounded-value here) to hex in google search.

Answer 6

That chart is not showing percents. "#90" is not "90%". That chart shows the hexadecimal to decimal conversion. The hex number 90 (typically represented as 0x90) is equivalent to the decimal number 144.

Hexadecimal numbers are base-16, so each digit is a value between 0 and F. The maximum value for a two byte hex value (such as the transparency of a color) is 0xFF, or 255 in decimal. Thus 100% is 0xFF.