Assuming you applied a Par Value to your shares when you incorporated, there are two ways to calculate Delaware Franchise Tax. It is often the case that the "Assumed Par Value" method results in the lowest franchise tax calculation.
Unfortunately, the State of Delaware does not have the data necessary to calculate your tax using the "Assumed Par Value" method, so they end up defaulting to the "Authorized Shares Method".
It is relatively easy to calculate the "Assumed Par Value" Method. We did an article on this at www.capgenius.com and will include a link to it below. The article includes an example of how to calculate both methods and step-by-step instructions. We have received multiple comments from companies who saved tons of money by using the alternative method, so check it out and we hope it helps!
If you do not have Par Value assigned, read the article that Dana links to as it is directly relevant to that situation.
Hope it helps. Please ping us with any follow-up questions either here or on twitter (@capgenius).