All income is taxable. Unless income is from a sell of a primary residence or from an inheritance. If your income is truly non taxable, then you don't need to do anything with it. It doesn't need to be recorded anywhere. Only taxable income is reported to the IRS. Basically, if you didn't get a W2 or a !099 for the income, then it is all yours and you don't report it. If you are talking about income earned as cash, then you shouldn't be asking that question on an open form, since it wold be addmitting that you indeed have taxable income.