The IRS states that it issues "most refunds within 21 days" of accepting the return. However, most individuals have actually reported a much faster turn around.
Many factors can end up delaying a refund being issued by the IRS, such as mistakes on the return, questionable information or repeat transmissions. Additionally, the IRS conducts random audits which can also delay the transmission of an electronic refund. However, once approved, most electronic refunds are issued within just a few days, often making it to the tax filer's bank account first thing in the morning the day that the refund is issued.