The cost to build a mansion will depend on the square footage of the mansion.
Mansions can be bigger than each other so that would factor into cost.
For a smaller square foot mansion the cost will be less than a larger square foot mansion.
Building mansions though cost from $300.00 per square foot so you're looking at at least 1 million dollars to 3 million dollars to build a mansion.
That doesn't even factor in the cost of the land the mansion will be built on either.
Typical lots for mansions are purchased for 1 million dollars just for the land to build the mansion.
To build a mansion it will take about a year to a year and a half to complete it and for it to be ready to be moved into.