The Siege Calculator will help you determine the siege of any monster at any level. This is a great tool to determine what level you must get your monster to produce a specific siege value. An example would be trying to piece together a unit that deals 120 siege damage which will guarantee taking a LV1 territory in one hit. Simply enter the starting siege for the unit and the target level, and the calculator will return the correct siege for that level.
*Special thanks to Arc Tech for developing this calculator!