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.
