According to IRS https://www.irs.gov/refunds/tax-season-refund-frequently-asked-questions, many different factors can affect the timing of your refund after IRS receive your return. Even though IRS issue most refunds in less than 21 days, it’s possible your refund may take longer. Also, remember to take into consideration the time it takes for your financial institution to post the refund to your account or for you to receive it by mail.
You should also need to know that some IRS tax returns take longer to process than others for many reasons, including when a return:
- Includes errors
- Is incomplete
- Is affected by identity theft or fraud
- Includes a claim filed for an Earned Income Tax Credit or an Additional Child Tax Credit. See Q&A below.
- Includes a Form 8379, Injured Spouse Allocation PDF, which could take up to 14 weeks to process
- Needs further review in general
IRS will contact you by mail when they need more information to process your return.
So in most cases you should expect your IRS tax return no more than 21 days.