According to the IRS website What to expect for Refunds This Year more than 9 out of 10 refunds are issued in less than 21 days after the IRS accepts the tax return when you e-file and choose direct deposit as your refund choice.
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.
For more on the timing of your refund please see this TurboTax FAQ.