When the return is filed, all tax, penalty and interest due must be paid.

One hundred 100 percent of the previous year's tax liability. For calendar year 2007, the interest rate will be 7 percent . The easy and accurate way to calculate penalties and interest.

Returns must be filed and payments remitted in the manner required by the due date. Calculations for old years and multiple year deficiencies. When the return is filed, all tax, penalty and interest due must be paid. By filing on time, you avoid the late filing penalty. Finance, which issues the refund checks, to withhold refunds for other reasons.