Retirement Income Planner

Social Security taxation follows a unique IRS formula that surprises many retirees. The government calculates your "provisional income" by adding half your Social Security to all other income. Single filers with provisional income below $25,000 pay zero tax on Social Security, while those above $34,000 may see up to 85% of their benefit taxed. For married couples filing jointly, the thresholds are $32,000 and $44,000. This calculator applies the exact IRS formula to determine your taxable Social Security amount.

Most states do not tax Social Security benefits, but ten states still do: Colorado, Connecticut, Minnesota, Montana, Nebraska, New Mexico, Rhode Island, Utah, Vermont, and West Virginia. Some of these offer partial exemptions or income-based phase-outs. If Social Security is a large portion of your retirement income, choosing a state that exempts it can save thousands annually. This is one reason Florida, Texas, and Nevada are popular retirement destinations.

Roth conversions before retirement can dramatically change your tax picture. Since Roth withdrawals are not counted as income, they do not increase your provisional income and therefore do not trigger Social Security taxation. Converting traditional IRA or 401(k) funds to Roth during lower-income years (for example, between early retirement and age 70) can reduce your lifetime tax bill. The trade-off is paying tax on the conversion amount now to avoid tax on withdrawals later.

Part-time work in retirement has an outsized tax impact because every dollar of earned income increases your provisional income, which can push more of your Social Security into the taxable range. A $10,000 part-time job might effectively cost you $2,000 to $3,000 in additional Social Security taxation on top of the income tax and FICA on the job itself. This calculator accounts for the FICA tax (7.65%) that applies only to earned income, plus the cascading effect on Social Security taxation.