1 lb. = 16 oz.
8 oz. = 1 cup
4 oz. = 1/2 cup
Hope this helps!
That works only for water (and similar liquids), potatocakes.
A cup of feathers does not weight 8 ounces and neither does a cup of lead. And neither does a cup of flour or sugar.
I'm not sure is if is what you're looking for. But I swear by this website, its never let me down!! 
http://www.onlineconversion.com/ Hope it helps!
Oops, I stand corrected, then! 
However, when I made this recipe that she's talking about, I'm pretty sure I used the measurements of 1/4 lb. equals 4 oz., which is 1/2 cup on my measuring glass, and the icing turned out fine.
You got lucky! Ounces measured by volume aren't the same as ounces measured by weight. The only way to be sure is to take a weight of whatever it is and then measure it. Then you'll know for sure what equals what - of that particular thing. Flour is different from sugar which is different from powdered sugar, etc. To make it even more confusing, Butter just happens to be the same, whether you're weighing it or measuring it. Other things....no.
Elliott1 I couldn't be happier you posted that website. Less than a month ago, my computer crashed and I lost everything. I had been hunting for that conversion site ever since. Along with a multitude of other sites I lost.
IT'S THE BEST AND SO ARE YOU FOR POSTING IT!
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