Converting yarn measurements

I purchased a pattern that gives the required yarn in grams. It calls for 100 grams of one type of yarn and 50 grams of another. I am from the United States. Our measurements are in Pounds and ounces or yards. I have no idea how much yarn to purchase.

Hi,
You can use Google for converting the measurements. 
Just type "convert grams into pound" and Google will help you.

Regards
Michaela 

100 grams are 3.53 ounce and 50 grams half of it. Is the type of yarn explained clearly?

I have the same problem with the grams too. Also 50 grams of one yarn is not the same on all yarns and I don't know how to judge It

Hi Mistydee, is there any yardage mentioned for that yarn, or any fiber content maybe? 50 grams is very little information, considering that 50 grams of a bulky or 50 grams of a fingering make a huge difference.