You see these two buttons all over the Internet. One has a significantly different meaning that the other, if only subconsciously. For most e-commerce sites on the web I would recommend using “Add to Cart”. “Buy Now”, although a strong call to action, implies an immediate commitment to buy. Visitors to your site can get scared away from clicking the button altogether if they think they will now be committed to buy.

“Add to Cart” implies that the item can sit in their shopping cart and they can think about it for a while with no commitment to buy. Yes its true that we may want the customer to purchase impulsively. Still though, people like to add items to their cart. They may not be ready to purchase right away, or they may want to seek out more information about the product.

As a case-in-point, one of the speakers at this year’s PubCon, gave the example of the EBay “Buy It Now” button. Every time he sees this button hes afraid to click it because he thinks EBay may now force him to buy this item from the seller.

Don’t take my word for it, though. You should try both and run your own A / B test to see which one converts at a higher percentage.