Tax Bracket Fill-Up Planner
Example: Current taxable income (after deductions): 75000 $ · Filing status (0 = Single, 1 = Married Filing Jointly): 0 · Fill up to this bracket rate (0 = fill current bracket only): 0 %
| Your current marginal bracket rate | 22.00% |
| Remaining room in current bracket | $28,350 |
| Amount to fill up (to current or target bracket top) | $28,350 |
| Tax cost to fill up that amount | $6,237 |
Worked example
A single filer with $75,000 in taxable income is in the 22% bracket. The 22% bracket runs from $48,475 to $103,350 — there is $28,350 of room remaining at the 22% rate. Converting $28,350 of traditional IRA money to Roth costs about $6,237 in federal tax (at 22%), filling the bracket completely. Any additional conversion above that would tip into the 24% bracket. If instead only $10,000 is converted, the tax cost is $2,200 — locking in the lower rate on that slice.
Frequently asked questions
Why is filling a lower bracket valuable?
Tax rates are not guaranteed to stay the same — and your income typically rises over your career. Converting IRA funds or realizing gains now at a lower bracket rate can be permanently cheaper than doing so later in a higher bracket. The fill-up strategy is most powerful in years when income temporarily dips (sabbatical, early retirement, between jobs).
Does the 0% long-term capital gains bracket follow the same structure?
Yes, the 0% LTCG bracket applies on top of ordinary income, up to $48,350 for single filers and $96,700 for MFJ in 2025. If your ordinary taxable income is below those thresholds, you can realize long-term capital gains up to the threshold at a 0% federal rate — a major planning opportunity.
What is the interaction between bracket fill-up and the NIIT?
The 3.8% Net Investment Income Tax kicks in at $200,000 MAGI for single filers ($250,000 MFJ) — and it stacks on top of capital gains rates. If filling your bracket pushes MAGI above those thresholds, the effective rate on investment income jumps by 3.8%. Model bracket fill-up with the NIIT threshold in mind.