I mailed my return so when will i hear back from the irs?

It is genuinely hard to predict at this time.  At present, the IRS is still facing quite a backlog of returns, with many taxpayers still waiting for their mailed in 2019 returns to be processed.  While processing returns is a priority for the IRS, reports from those who have mailed in returns recently are not particularly optimistic for a turnaround time. 

There is some variation between the IRS centers (one may be more backed up than another), but they are all experiencing a much higher than usual processing time (usual for a mailed return was about 12-16 weeks or so.)  Currently, it is taking longer than this in some cases for the returns to even show up as received. 

I wish I could give you a more precise timeline or even a better guess, but it is very difficult to predict currently.  Much more patience than average is required this tax season for all filers, even those filing electronically.