Is it 21 days or 21 business days for irs to issue refund ? I seen one turbo tax expert say mon/fri only . Just worried because my 21 days will be up on the 8th if it’s 21 days & the 16th if it

[DoninGA]

The 21 days is not a magic number.  It is just a Target set by the IRS to issue a federal tax refund.  It is NOT a guarantee.

If accepted by the IRS use the federal tax refund website to check the refund status - https://www.irs.gov/refunds

After the tax return has been Accepted by the IRS (meaning only that they received the return) it will be in the Processing mode until the tax refund has been Approved and then an Issue Date will be available on the IRS website.
See this IRS website for federal tax refund FAQ's - https://www.irs.gov/refunds/tax-season-refund-frequently-asked-questions