How long do I have to amend or claim a refund?
In general you can claim a refund within 3 years from the date you filed the original return, or within 2 years from the date you paid the tax if that is later. After that the refund is usually lost, so do not wait.
Amended returns for recent years can be e-filed, which speeds up processing.
Filing years you missed
Each year must be filed on that year’s forms and rules. The IRS generally expects the last six years to be filed before it considers you current. Filing late returns stops the failure-to-file penalty from growing, and if you were owed refunds in recent years you may still be able to claim them.