A reasonable royalty is a calculation of how much the patent holder would have received from the defendant in a hypothetical license negotiation taking place at the time the infringement began. In making this determination, the court will assume that the parties would have entered into the hypothetical negotiations as a willing buyer and a willing seller, and that the patent is assumed to be valid, enforceable and infringed. The amount of the reasonable royalty is determined by analyzing a number of different factors, including whether there are other licenses by the patent holder, or other comparable licenses, which would tend to prove an established royalty; the established licensing policies of the patent holder; the nature and scope of the license; the commercial relationship between the licensor and licensee; the profitability of the product using the license; and the portion of the profits of the product that is due to infringing the patent versus profits from non-infringing elements of the product.