You can get a free transcript online of your Record of Account which will shown the date the extension was received by the IRS. - https://www.irs.gov/individuals/get-transcript
Or you can complete, mail or fax a Form 4506-T to get this transcript type - http://www.irs.gov/pub/irs-pdf/f4506t.pdf
Or you can go to the following TurboTax website for the status of the e-filed extension - https://shop.turbotax.intuit.com/efile/efile_status_lookup.jsp
