Tax Bracket Fill Tool

What if a low-income year in early retirement is actually a tax bargain you’re letting expire? It usually is. The empty space in your low brackets is a use-it-or-lose-it opportunity, and most retirees leave it on the table. This tool shows you exactly how much income you can pull forward at today’s cheap rates before the next bracket kicks in.

The decision it solves

Tax brackets are marginal, which means only the income inside each band pays that band’s rate. The years between leaving work and starting Social Security and RMDs are often your lowest-income years ever. Your low brackets sit half-empty.

Here’s the part the autopilot misses. Those empty brackets don’t roll over. Income you don’t realize at 12% this year doesn’t bank you a discount later. It just means the same dollars come out at 22% or 24% down the road, once RMDs and Social Security stack up. The decision is simple to state and easy to skip: how much income should you deliberately create this year to fill the cheap brackets before they vanish?

How the math works

Start with your taxable income for the year after the standard deduction, which for 2026 is $32,200 for a married couple and $16,100 single. Then look at where the brackets break. For a married couple in 2026, the 10% bracket runs to $24,800 of taxable income, the 12% bracket to $100,800, and the 22% bracket to $211,400.

The tool measures the gap between your current taxable income and the top of whichever bracket you’re trying to fill, then tells you how many dollars of “voluntary” income you can add to reach it. You fill that space on purpose, usually with a Roth conversion or a strategically timed IRA withdrawal. The cost is the tax at that low rate. The payoff is moving money out of a future high-rate event at a discount you’ll never see again.

A worked example

A married couple, both 65, retired, living on $60,000 from a taxable account this year. After the $32,200 standard deduction, their taxable income is roughly $28,000, barely into the 12% bracket.

The top of their 12% bracket is $100,800. That leaves about $72,000 of room before they’d touch the 22% rate. The tool’s recommendation: convert roughly $72,000 from their traditional IRA to a Roth. They pay 12% on it, around $8,600. Those dollars now grow tax-free, will never face an RMD, and won’t someday come out at 22% or higher once Social Security and forced withdrawals fill the lower brackets for them.

Skip the move and the brackets close empty. A 12% bracket left unused this year often becomes a 24% withdrawal a decade from now. That gap is the whole game.

The hidden ceiling most miss

Filling brackets has a second-order cost you have to watch. Pushing more income can tax more of your Social Security, trip an IRMAA Medicare surcharge two years out, or bump capital gains from the 0% rate into the 15% rate. So the real target often isn’t the top of a tax bracket. It’s the lowest of those ceilings. The tool stacks all of them and stops you at the first one that actually binds, not just the bracket line. See tax bracket management in retirement for how the limits interact.

If your accounts are large

The bigger your traditional IRA, the more valuable every low-bracket year becomes, because each unfilled bracket is a future RMD taxed at your highest rate. With a seven-figure IRA, the plan is to fill the cheap brackets every single year of the gap, methodically, until RMDs begin. Years pass. The window closes one bracket at a time.

Treat the empty bracket like fruit that rots. Fill it this year or pay full price for it later.