However, if you just don't pay, you have a failure to pay penalty, which is currently only 0.5 % of the unpaid taxes per each month late. (thecollegeinvestor.com)
If you don't file your tax return, you will pay a failure to file penalty, which is currently 5 % of the unpaid taxes per month late. (thecollegeinvestor.com)
That penalty is usually 0.5 % of your unpaid taxes per month. (policygenius.com)