Using the live silver price and the specifications above, these are the numbers required to calculate melt value:
$19.63 = silver price / ounce on Aug 01, 2013.
.90 = silver %
$3.1256 = copper price / pound on Aug 01, 2013.
.10 = copper %
12.5 = total weight in grams
.0321507466 = ounce/gram conversion factor
.00220462262 = pound/gram conversion factor (see note directly below)
The CME uses pounds to price copper and that means we need to multiply the metal price by .00220462262 to make the conversion to grams. The silver price is based in troy ounces and that means we need to multiply the metal price by .0321507466 to make the conversion to grams.
1. Calculate 90% silver value :
(19.63 × .0321507466 × 12.5 × .90) = $7.1000905022
$7.1000 is the rounded silver value for the 1964 silver Kennedy half dollar on August 01, 2013. This is usually the value used by coin dealers when selling these coins at melt value. However, the total melt value is continued below.
2. Calculate 10% copper value :
(3.1256 × .00220462262 × 12.5 × .10) = $0.0086133
3. Add the two together :
$7.1000905022 + $0.0086133 = $7.1087038022
$7.1087038022 is the total melt value for the 1964 silver Kennedy half dollar on August 01, 2013.