Magento

i am selling carpet and i am entering different sizes in a product page by custom options. And i want to inventery for every size product in custom options. How can i do ?

Hello,

Custom options do not allow to track inventory.  To be able to do that, you need to create configurable products.

Check this article with comparison of custom options and configurable products -
http://www.mag-manager.com/useful-articles/tipstricks/simple-products-with-custom-options-vs-configurable-products

Also you might find useful the article on how to create configurable products -
http://www.mag-manager.com/useful-articles/tipstricks/what-is-magento-configurable-product-how-to-create-magento-configurable-product

Hope it will be useful.