Roth Conversion Calculator
A conversion counts as income this year. Convert too much and part of it spills into a higher band, taxed at exactly the rate you were trying to dodge. This shows how much room you have before that happens.
Converting leaves you ahead by
-
- Room before the next band
- $0
- Tax you would owe this year
- $0
- Actually lands in the Roth
- $0
- Roth is worth later
- $0
- Left alone, after tax later
- $0
Where the money goes
Each block is sized by its share, so you can see whether room before the next band or actually lands in the Roth is the bigger part without reading a single number.
Move it and watch
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at {v} for your taxable income before converting
And what you can change
Why your own figure may differ
Where your bands sit this year
The line to watch is the top of your current band. Converting up to it is cheap; converting past it is not.
| Band | Up to | Room from where you are | Tax on filling it |
|---|
Room = the top of the band minus your taxable income before converting. Convert within that and every dollar is taxed at your current rate. Convert past it and the excess is taxed at the next rate up.
Roth conversions: real examples
Three conversions, three different outcomes. Click any card to load it.
- A low-income year
Converting $10,000 at 12%
A $40,000 income leaves room inside the 12% band.
It fits entirely inside the 12% band, so every dollar is taxed at 12% and never again. The tax bill is just $1,200.
Load this scenario in the calculator → - Paying tax the weak way
The same conversion, tax from the pot
Only what is left makes it across.
Just $8,800 goes across instead of $10,000. That missing $1,200 compounds for twenty years and costs you far more than it looks.
Load this scenario in the calculator → - Converting too much
$30,000 on a $40,000 income
The conversion spills past the 12% line.
Only $10,400 fits at 12%. The rest jumps to 22%, lifting the average rate on the whole conversion - the exact thing you were trying to avoid.
Load this scenario in the calculator →
Common questions about Roth conversions
What is a Roth conversion?
Moving money from a Traditional account into a Roth, on purpose, and paying the tax now rather than later. You do it in a year when your tax rate is unusually low, so those dollars get taxed cheaply and then never again.
When does it make sense?
In a low-income year. Between jobs, early retirement before your pension or Social Security starts, a year with a big business loss, or any year your income dips. The whole idea is paying tax at a low rate instead of a high one later.
What is the trap I should know about?
The converted amount counts as income that year. Convert too much and part of it gets pushed into a higher band and taxed at that higher rate - which defeats the purpose. This tool shows how much room you have below the next band line before that happens.
Should I pay the tax from the money I am converting?
No, if you can possibly avoid it. Paying from the converted money means less makes it across, and that shortfall compounds for decades. The tool shows both ways. Paying from outside money is always the stronger version, and often by a lot.
Why does a large Traditional balance cause problems later?
Because you are eventually forced to take money out whether you need it or not, and every dollar is taxed as income. A large balance can force large withdrawals that push you into higher bands and affect other things too. Converting earlier shrinks that future problem.
Can I undo a conversion?
No. Reversing conversions used to be allowed and is not any more. Once you convert, the tax is owed for that year. That is exactly why it is worth working out the amount carefully before doing it rather than after.
The guide behind this calculator
Tax bands are for the 2026 tax year, read from Revenue Procedure 2025-32, Section 4.01 (Tax Rate Tables). Checked 2026-08-17.