New Jersey’s Income Tax is a “pay-as-you-go” tax. You must pay the tax as you earn or receive income throughout the year.
If the balance of tax due with your return is more than $400, and you did not pay your required estimated payments, you will be charged interest on the underpayment. This is true even if you pay all the tax due by the return due date (April 15th for calendar year filers).
For estimated tax purposes, the year is divided into four payment periods, each with a specific due date. If your estimated payments are made late, interest charges will be assessed from the due date of the payment(s) to the actual payment date(s).
Interest is assessed at the annual rate of 3% above the prime rate. At the end of each calendar year, any tax, penalties, and interest still due become part of the balance on which interest is charged. Technical Bulletin TB-21(R) shows current and historical interest rates.
If you failed to make all of the required estimated payments, you should complete Form NJ-2210 62 kb, Underpayment of Estimated Tax by Individuals, Estates or Trusts, to determine if interest is due and calculate the amount.
Additional information Concerning Estimated Tax for Taxpayers Earning Over $150,000 also is available.