The length of time you should keep a document depends on the action, expense, or event which the document records. Generally, you must keep your records that support an item of income, deduction or credit shown on your tax return until the period of limitations for that tax return runs out.
The period of limitations is the period of time in which you can amend your tax return to claim a credit or refund, or the IRS can assess additional tax. The information below reflects the periods of limitations that apply to income tax returns. Unless otherwise stated, the years refer to the period after the return was filed. Returns filed before the due date are treated as filed on the due date.
Note: Keep copies of your filed tax returns. They help in preparing future tax returns and making computations if you file an amended return.