By law, the IRS cannot issue refunds before mid-February for tax returns that claim the Earned Income Tax Credit (EITC) or the Additional Child Tax Credit (ACTC).
The IRS expects the earliest EITC/ACTC related refunds to be available in taxpayer bank accounts or on debit cards starting on Feb 27, 2019, if they chose direct deposit and there are no other issues with their tax return.
NOTE: Even though the IRS issues most refunds between 7 and 21 days, some tax returns require additional review and can take longer than 21 days for refunds to be issued.
Source: Publication 2043 (Rev. 1-2019)