Rip the Band-Aid, or the Ladder?

Real Conversations

Once someone truly absorbs the all-pretax problem from last week, a predictable instinct kicks in. I've heard it on multiple real calls (details changed and blended so nobody is identifiable):

"If the tax bill is coming anyway, why not just rip the band-aid off? Convert the whole thing in a year or two and be done with it."

I love the decisiveness. The math does not. I've now modeled this comparison for several different households, and the fast road loses every time, usually by six figures. Here's the anatomy of why, on one composite couple.

The setup

Both 62, just retired, $1.4M in Traditional IRAs, $58K of combined Social Security planned at 67, living expenses covered by cash and taxable savings for now. Hypothetical composite, invented numbers. Two roads out of the pretax pile:

Road one, the cram: convert $700K in each of the next two years. Done by 64.

Road two, the ladder: convert roughly $110K a year for ten years, sized each year to fill the brackets through 22% and stop under the relevant cliffs.

Both roads empty the pile before RMDs. Same destination. Watch the tolls.

What the cram actually costs

A $700K conversion doesn't get taxed at "your bracket." It BECOMES your bracket. The first slices fill 10%, 12%, 22%, 24%, and then the bulk of it lands in 32%, 35%, and 37% territory. Blended federal cost: somewhere around 30% on average, versus the 15-18% blend the ladder achieves. On $1.4M, that spread alone is roughly $180,000 of extra tax for the privilege of speed.

And the cram's collateral damage doesn't show up on the conversion-year return. At 62 and 63, those monster MAGI years land squarely in the IRMAA lookback: their first two years of Medicare premiums arrive with maximum surcharges, thousands per year, unappealable because conversions aren't a qualifying life event. If either spouse needed ACA coverage, the subsidies are vaporized for two years. And the tax on the conversion has to be paid from somewhere: at that size, usually from the converted funds themselves, which shrinks the very Roth you were building.

There's also a subtler cost: the cram spends ALL the low-bracket space of two years and then wastes the low-bracket space of the next eight. Years 64 through 73 sit there with empty 12% and 22% brackets and nothing left to convert into them. Bracket space doesn't roll over. The cram torches it.

What the ladder banks

$110K a year, sized annually against that year's brackets, IRMAA tiers, and (before 65) the ACA cliff, with taxes paid from taxable savings. Every dollar converts in the 12-22% range. Social Security gets delayed toward 70 partly BECAUSE the ladder needs the low-income runway, which quietly buys the bigger survivor check too.

Ten years later, both roads arrive at the same place: pretax pile empty, RMD problem dissolved, Roth compounding tax-free. The ladder just arrives roughly $150K to $200K richer, with no premium surcharges along the way.

When faster is actually right

The cram isn't always wrong. A known short window changes the math: a spouse's serious diagnosis makes the final joint-filing years precious. A temporary valuation dip makes converting more shares per dollar attractive. And genuinely enormous pretax balances ($4M+) sometimes can't fit through a ten-year ladder at reasonable brackets, so some 24% conversions become the least-bad option. Speed is a tool. It's just rarely the default.

The band-aid metaphor is the whole problem. This isn't a band-aid. It's a mortgage, and nobody pays off a mortgage in two years by choice when the rate for going slower is lower.