People email me a version of the same hopeful question: how do I convert my traditional IRA to a Roth without paying taxes? I get why they ask. A Roth conversion lands a tax bill in the same year, and nobody enjoys writing the IRS a check for moving their own money from one pocket to another. So let me give you the honest answer first, and then the part that actually helps — the move that gets you as close to “tax-free” as the law allows.
The honest answer first
You cannot convert pre-tax IRA money to a Roth without it being taxed as ordinary income that year. Anyone telling you there’s a clean way to convert a traditional IRA to Roth without paying taxes is either confused or selling something. The narrow exceptions only shrink the taxable slice — they don’t erase it. If part of your IRA is already after-tax money (nondeductible contributions you tracked on Form 8606), that portion comes out tax-free, but the pro-rata rule means you can’t just cherry-pick it; the IRS makes you convert a blended slice. (This is a your-money-your-taxes topic, so treat everything here as how I think about it, not personal advice.)
So the real question isn’t “how do I avoid the tax.” It’s “how do I pay the least tax, and pay it in a way that doesn’t quietly sabotage the conversion.” That distinction turns out to be the whole game.
The move that feels almost tax-free: pay the tax from your brokerage
Here’s the trap most people fall into. Say you convert $50,000 and let the withholding come straight out of the conversion. Only about $38,000 actually lands in the Roth — the rest went to the IRS before it ever got there. And if you’re under 59½, that withheld chunk can even get dinged with the 10% early-withdrawal penalty, because the IRS treats money that didn’t make it into the Roth as a distribution. (That’s a genuinely expensive way to do a “free” conversion.)
The better move is to pay the conversion tax out of your taxable brokerage account or savings — outside money — so the full $50,000 converts and starts compounding tax-free for the rest of your life. Over a couple of decades that difference compounds into real money. Paying the tax with outside cash is the single thing that makes aggressive conversions worth doing; pay it from inside the IRA and you’re just shoveling the same dollars back and forth while shrinking the tax-free pile you were trying to build.
That’s the version of “without paying taxes” that’s actually true: you still pay the tax, but you pay it in a way that keeps every dollar of the conversion working for you instead of leaking 20-something percent on the way in.
Why I had to rebuild my own calculator
I built a free Roth conversion calculator a while back, and I’ll own a real blind spot in the first version: it sized the conversions and showed you the tax, but it quietly pretended the money to pay that tax appeared out of thin air. All three accounts just grew, untouched. Useful for sketching a conversion schedule, sure — but that’s not how anyone’s actual retirement works. (Nobody’s brokerage account politely covers the tax bill while staying exactly the same size.)
So I rewrote the engine from the ground up to model cash flow. Now it draws your living expenses out each year, pays the tax on your income and your conversions from your accounts in a sensible order — taxable brokerage first, then the traditional IRA, and the Roth only as a last resort — and it respects the pre-59½ penalty where it bites. In other words, it finally does the exact thing this whole post is about: it pays the conversion tax from the right account and shows you what that does to your balances, year by year.
What the tool optimizes now
Once the cash actually moves between accounts, the three balances stop being interchangeable — a dollar in the Roth is worth more than a dollar in the pre-tax IRA, which is worth more than a dollar of brokerage money carrying an unrealized gain. That changes what “best” even means. The old version chased the lowest lifetime tax, but once your brokerage is paying the bill, “lowest tax” just tells you to convert nothing. So the new version optimizes for what you actually care about: the most money left after tax at the end.
You enter your traditional IRA, your Roth, your brokerage balance (including how much of it is unrealized long- and short-term gains), your annual spending, and your Social Security, and it finds the conversion schedule that leaves you the most after-tax wealth — then shows the year-by-year drawdown so you can hand the plan to your CPA. In one example I ran (a 62-year-old single retiree with a $1.2M IRA, a $300K brokerage, and $60K of annual spending), paying each year’s conversion tax out of the brokerage instead of the IRA was the whole difference between a plan that builds a large tax-free Roth and one that just treads water.
What it still doesn’t do, so you know
I’d rather tell you the limits than let you over-trust a free tool. It’s federal tax only right now — no state income tax — and it doesn’t yet model IRMAA (the Medicare premium surcharge a big conversion can trigger two years later), the 3.8% net investment income tax, or the ACA premium subsidies an early retiree can lose by adding conversion income before age 65. Any of those can change the math, and they’re next on my build list. Until then, treat the output as a strong first draft of a conversion plan, not the final word — and run anything real past a tax professional who can see your whole picture.
If you want to see your own numbers, the free Roth conversion calculator is right here — no signup, no email wall, just your numbers and a plan you can download. Plug in your accounts and see what paying the tax from the right place does over the next thirty years.
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