Maximum Refund Guarantee / Maximum Tax Savings Guarantee - or Your Money Back – Individual Returns: If you get a larger refund or smaller tax due from another tax preparation method by filing an amended return, we'll refund the applicable TurboTax federal and/or state purchase price paid.This guarantee is good for the lifetime of your personal, individual tax return, which Intuit defines as seven years from the date you filed it with TurboTax. 100% Accurate Calculations Guarantee – Individual Returns: If you pay an IRS or state penalty or interest because of a TurboTax calculation error, we'll pay you the penalty and interest.