Roth conversion calculator
Should you convert traditional IRA / 401(k) money to Roth? It depends on whether you'll be in a higher or lower tax bracket in retirement. Run the math here.
Inputs
Convert.
You'd come out ahead by about $4K in retirement.
Path 1 — Leave in Traditional
Path 2 — Convert to Roth
Conversions are usually multi-year decisions.
The optimal strategy is often a conversion ladder — converting a slice each year to fill up lower tax brackets without spilling into higher ones. Granary models the full ladder, year-by-year, against your projected income, RMDs, and IRMAA tiers.
See the full ladder →How Roth conversions work
A Roth conversion moves money from a traditional account (Traditional IRA, Traditional 401(k)) into a Roth account (Roth IRA, Roth 401(k)). The amount converted is taxed as ordinary income that year. After conversion, the money grows tax-free and qualified withdrawals in retirement are tax-free.
When does a conversion make sense?
- You expect to be in a higher tax bracket later. Pay tax now at today's rate; avoid the future higher rate.
- You're in a low-income year. Early retirement before Social Security and RMDs is a classic window — you can convert and stay in the 12%-22% brackets.
- You want to reduce future RMDs. Roth accounts have no RMDs during your lifetime, so converting reduces the amount you're forced to withdraw later.
- You have other money to pay the tax. Paying conversion tax out of the converted amount itself is much less efficient — pay from a taxable account instead.
When does it NOT make sense?
- You expect to be in a lower bracket in retirement.
- You're in your peak earning years already (high marginal rate).
- You don't have liquid taxable money to pay the conversion tax.
- You're close to a tax cliff (IRMAA, ACA subsidy threshold) — converting can push you over and cost more than the conversion saves.
What this calculator simplifies
We assume one-shot conversion, flat tax rates, and ignore IRMAA / ACA cliffs. Real conversions are usually staged across multiple years, and small bracket-fill amounts at low rates dominate the math. For the proper analysis — accounting for your specific brackets, RMDs, and IRMAA tiers — use Granary's Tax Strategy page.