If some contributions to your pension or annuity plan were previously included in gross income, you can exclude part of the distributions from income. You must figure the tax-free part when the payments first begin. The tax-free part generally remains the same each year, even if the amount of the payment changes. However, the total amount of your pension or annuity that you can exclude from income is generally limited to your total cost (sometimes referred to as "basis" or "investment in the contract"). For more information on how to determine your total cost, refer to Publication 575, Pension and Annuity Income.
The General Rule
If you receive annuity payments from a nonqualified retirement plan, you must use the General Rule. Under the General Rule, you figure the taxable and tax-free parts of your annuity payments using life expectancy tables that the IRS issues. For a fee, the IRS will figure the tax-free part of your annuity payments for you. For more information, refer to Publication 939, General Rule for Pensions and Annuities.
The Simplified Method
Generally, if you begin receiving annuity payments from a qualified retirement plan, you use the Simplified Method to figure the tax-free part of the payments. A qualified retirement plan is a qualified employee plan, a qualified employee annuity, or a tax-sheltered annuity plan or contract (refer to Publication 575 for definitions). Under the Simplified Method, you figure the taxable and tax-free parts of your annuity payments by completing the Simplified Method Worksheet in the Form 1040 Instructions (PDF) or in Publication 575. For more information on the Simplified Method, refer to Publication 575, or if you receive United States Civil Service retirement benefits, refer to Publication 721, Tax Guide to U.S. Civil Service Retirement Benefits.