How much can you convert before leaving a tax bracket?

The basic bracket-room idea

Start with gross ordinary income before the conversion: wages, pensions, taxable interest, the taxable part of Social Security, and any other IRA withdrawals, before deductions. Subtract the standard deduction for your filing status, which for 2026 is $32,200 married filing jointly, $16,100 single, and $24,150 head of household. What is left is taxable income, and the brackets apply to taxable income, not gross. The gap between taxable income and the top of the bracket you are willing to fill is rough conversion room before the next marginal rate begins.

An example

A married couple filing jointly with $60,000 of gross income has $27,800 of taxable income. The 12% bracket runs to $100,800 of taxable income, so $73,000 of conversion fits before the 22% rate begins. Put another way, the 12% bracket ends at $133,000 of gross income. When gross income is below the standard deduction, the unused part shelters conversion dollars at 0%.

Those figures use the standard deduction alone, as for a couple under 65. The Roth conversion planner adds the age-65 addition from your 65th year, and assumes a married couple are both 65 or older once you are: $3,300 more room in 2026, so the 12% bracket ends at $136,300 of gross income. It leaves out the temporary senior deduction, which can add as much as $12,000 more for a couple through 2028.

Why “fill the bracket” is not the whole plan

Bracket room is useful, but it is not a full tax return. A Roth conversion can interact with Medicare premiums, Social Security taxation, ACA subsidies, credits, deductions, state taxes, and investment income. The Roth conversion planner counts Social Security taxation, Medicare surcharges, and state tax at two flat rates in its household simulation and names the rest as not modeled, and the Real Marginal Rate Explorer shows what Social Security taxation, capital gains, and IRMAA do to the cost of each extra dollar.

Use the tools as a bracket ruler

The Roth conversion planner applies the same arithmetic to each year of a projected retirement, Social Security included: it shows the rate on each slice of a conversion in the cheapest years, where a 12% bracket can cost 22.2% while benefits are becoming taxable, and how far converting is worth going against three possible future rates. Its plan can fill a chosen bracket every year, and the household simulation then shows what that does against converting nothing.

The RMD & IRMAA Horizon solves, for each year before required distributions begin, the conversion that fills the 12%, 22%, and 24% brackets, counting the Social Security each conversion makes taxable.