Yes. When you convert funds from a traditional IRA or 401(k) to a Roth IRA, the taxable portion of the converted amount is included in your New Jersey gross income for the year of conversion. You will owe NJ income tax on it at your applicable rate, which ranges from 1.4% to 10.75% depending on your total income.
What Makes NJ Different From the Federal Treatment
At the federal level, the entire conversion from a pre-tax traditional IRA is typically taxable. In New Jersey, the calculation can differ because NJ did not allow a deduction for traditional IRA contributions when they were made. This means the contributions themselves were already taxed by NJ — they are your "basis" and are not taxed again upon conversion.
Only the earnings and any pre-tax employer contributions (such as amounts rolled over from a 401(k)) are subject to NJ tax on conversion. If your IRA consists entirely of a 401(k) rollover, most or all of the conversion will be taxable for NJ purposes. If you made after-tax IRA contributions over the years, some portion of the conversion may be NJ tax-free.
Tracking your NJ basis requires keeping records of your original contributions. The NJ Division of Taxation provides guidance in Technical Bulletin GIT-1&2 on how to calculate the taxable and excludable portions of retirement account distributions.
Why NJ Residents Still Convert Despite the Tax
Paying tax on a Roth conversion now may seem counterintuitive, but for New Jersey residents specifically, there is a powerful reason: once funds are in a Roth IRA, qualified withdrawals in retirement do not count toward the gross income thresholds that determine your eligibility for the NJ pension exclusion.
This means Roth withdrawals can provide retirement income without pushing you over the $100,000 or $150,000 income cliffs — potentially saving you from losing a pension exclusion worth tens of thousands of dollars in tax savings over the course of your retirement.
For a detailed explanation of how this strategy works, including timing, amounts, and examples, read our comprehensive guide: Roth Conversions and New Jersey Taxes: A Strategic Guide.
Estimate Your Tax
Use our free NJ Retirement Tax Calculator to model how your retirement income picture changes with and without Roth conversions, and how it affects your pension exclusion eligibility.
For personalized Roth conversion planning, call 732-200-2877 to schedule a complimentary consultation.