https://www.irs.gov/refunds
If the IRS has actually sent the funds, the IRS says to allow up to 5 days due to variations in bank processing procedures and times. But it usually doesn't take that long.
However, there may be another link in the chain that you can check in the meantime if you used the following service:
Did you have any TurboTax fees that you chose to pay out of the Federal refund? If so, the funds go first from the IRS to a temporary account at an intermediary bank where the fees are subtracted. Then that intermediary bank sends the rest of the funds on to your bank (or card.) If you used that method to pay fees, and if the IRS has actually released the funds, we can tell you how to check on the funds at the level of the intermediary company (SBTPG).