Enter in the proper column(s) the total number of gallons of fuel from your paid fuel invoices, on which Iowa fuel tax was paid and which were placed in your fuel storage tanks during the tax year. Invoices must be kept for three years after your return is filed as proof of your credit. Gasoline or special fuel used in motor vehicles for off-loading procedures or used in watercraft, other than for commercial fishing, should not be included.

Fuel Tax Rates
Gasoline: .21 per gallon
Gasohol: .19 per gallon
E85: .19 per gallon
Undyed Diesel Fuel: .22.5 per gallon
Special Fuel (LPG): .20 per gallon