Iowa Code § 535.1: Denominations of money.

The money of account of this state is the dollar, cent, and mill, and all public accounts, and the proceedings of all courts in relation to money, shall be kept and expressed in the above denominations. Demands expressed in money of another denomination shall not be affected by the provisions of this section, but in any action or proceeding based thereon it shall be reduced to and computed by the denominations given.