It depends on the total tax due, not the outstanding balance. 

Here is the language from OH: 

The penalty imposed may not exceed the greater of (i) $50 per month up to $500, or (ii) 5 percent per month of the tax due shown on the report up to 50 percent. Additional penalties may be imposed for filing a fraudulent report and/or for filing a fraudulent refund claim.

Source: https://www.tax.ohio.gov/faq/tabid/6315/Default.aspx?QuestionID=111&AFMID=11354