How to change the price of all the products with a constant variable according the weight of the products in wordpress?

I want to change the price of the products according to the weight with a variable amount. Such as silver, as the price changes on day to day basis so the price will be calculated with the amount I insert for 1gm silver. For example, a product is of 300gm and the price for 1 gm silver is 2000 bucks then 300*2000 = 600,000 bucks. The silver price will change daily and the price will be calculated according to that for all the products. Is there any plugin available for that or if it is possible with some code change I can do that. Help me out with this issue. Thanks

via Chebli Mohamed