Thank you so much for your reply!

I have two more related questions.

If I file the Form 4868 by April 15th and have a tax balance unpaid, do I get to avoid the late filing penalty, despite the unpaid balance?

I found a source online that says the interest cost on the unpaid balance of tax is about 3% daily, and it is compounded daily. The IRS instructions don't say anything about charging and compounding daily, which would be a very rapid increase in cost. Do they do that? If not, do they compound monthly?

The reply from this morning said to see a link for the current interest rate used by the IRS, but there was no hyperlink, please point me in the right direction to where I can find it.

Thank you so much again, I really appreciate it!