The IRS reports that they issue 9 out of 10 tax refunds within 21 days, it's possible your return may require additional review and take longer to process. Where’s My Refund? has the most up to date information available about your refund. The tool is updated daily (usually overnight) so you will just usually need to check once a day.
Please see these TurboTax FAQ's on why some tax return refunds may take a while to be released and what steps you can take:
If you are concerned and it's been over 21 days since your tax return was accepted by the IRS and you decide to call them here are some tips when contacting the IRS at 1-800-829-1040:
Please see this TurboTax FAQ on what to have ready before you contact the IRS: https://ttlc.intuit.com/community/irs/help/what-do-i-need-if-i-call-the-irs/00/27378.
If you are anticipating a state tax return refund those processing times vary from state to state. To check on a state refund please visit your state Department of Revenue website.