The guarantee is a commitment (either written or oral) made by the manufacturer to repair, replace or even refund the amount if the product does not meet said performance. It applies to either products or services or anything else.
The warranty means a written promise provided by a company to its customers to repair or replace the part of the item purchased if it’s found to be defective within a specified time. The warranty applies to only products or goods, unlike the guarantee. Moreover, a warranty can be bought to extend the warranty period.