What is considered "not filing in time" ?

[_confused_]

hi,

I found some income wasn't reported in the last year's return and I need to amend my return.  Since I owe some tax, I will need to pay the interest/penalty, and I'm trying to figure out the rough amount that I need to pay.

The document says the penalty for not filing in time is 5% a month, but I wonder what is considered "not filing in time".  Is filing the original return in time but amending it many months later considered "not filing in time" because I failed to report some income in the original return ?

In the hypothetical scenario that I amend the return(note the original return was filed in time) and I owe $600 with the amendment, and  11 months past due date. What would be the penalty, interest, other than the tax I owe ?

I'd appreciate if you could comment.

[KathrynG3]

Specific dollar calculations even hypothetically may still not be useful for your circumstances.

The penalty for late payment penalties would begin when the return was due, April 15, 2020, if no extension was filed. Interest compounds daily until the tax bill is paid.

You may be eligible for penalty relief. call the number on the top right corner of your IRS Notice, or call the IRS at 800-829-1040.

For more information, see: 

What's the IRS penalty if I miss the April 15 filing deadline? for an overview.

Understanding Penalties and Interest | Internal Revenue Service for more specifics.