Backdoor Roth IRA Calculator

The annual IRA contribution limit applies to regular Traditional and Roth IRA contributions together. For 2026, the published limit is $7,500, or $8,600 when the age-50 catch-up applies, and eligible taxable compensation can impose a lower limit. The 2024 and 2025 limits are $7,000 and $8,000. A Roth conversion is not a regular annual contribution and is not capped by those dollar limits. The planning controls therefore do not overwrite a separately entered gross distribution.

A contribution tax year can differ from the calendar year when money is actually contributed or converted. Select both year roles deliberately. An earlier-year contribution must not be added again as a new contribution for the later conversion year when it is already reflected in prior basis. A contribution for the conversion tax year that was made after December 31 has a different treatment: it enters total basis but is removed from the current allocation numerator by line 4. The worksheet asks for these facts rather than inferring them from an account’s cash movement.

Start with prior adjusted basis and nondeductible contributions for the conversion tax year. Their sum is the total basis available to carry through the worksheet. Subtract applicable contributions made after year-end to obtain the numerator used for the current distribution allocation. The denominator includes aggregate December 31 Traditional, SEP and SIMPLE IRA value, relevant outstanding rollovers, other distributions and the gross distribution associated with the conversion. Enter ending fair market value including basis, and do not add basis to that value again.

Net converted dollars and other or withheld distributions recover basis proportionally. The numbered flow shows the basis recovered by each group and the amount carried forward. A ratio above 1 is capped at 1; basis can legitimately exceed current assets after investment losses, so this alone is not an impossible input. With no distributions, the ratio is not applicable and basis carries forward. Cent allocation is disclosed separately from actual filing rounding, and the displayed four-place ratio is not substituted for the full calculation ratio.

The current estimate multiplies the taxable gross distribution used for conversion by the selected combined marginal rate. It does not calculate the household’s progressive federal tax, credits, state-specific basis or complete tax liability. Withholding is part of the IRA distribution rather than an extra Roth contribution: those dollars do not reach Roth and receive their own share of basis. When actual withholding differs from estimated tax, current allocation can still be known even though payment or refund timing is outside the future strategy model.

The optional future comparison assumes one conversion, constant selected returns and tax rates, qualified Roth withdrawal treatment, and no later contributions. Paying tax from outside funds has an opportunity cost, illustrated with an explicit hypothetical taxable-investment rate and a constant 1.5% dividend yield. These are assumptions, not inferred legal tax rates or forecasts. Unknown future inputs leave that comparison unavailable while a known current tax remains visible. Sensitivity results change ending IRA value only as a hypothetical; a zero-value reference does not establish that an employer-plan rollover is permitted.

Use all personal Traditional, SEP and SIMPLE IRA accounts in the ordinary allocation, whether entered as one aggregate value or as generic account rows. The worksheet needs types and amounts rather than institution names or account numbers. If a relevant December 31 value is unknown, keep it unknown: the result stays provisional while known contribution and basis facts remain visible. Review special repayments, inherited accounts, deductible contribution changes, recharacterizations, QCD or HSA transfers, RMD restrictions, penalties and state treatment separately before relying on a filing calculation.

Edits do not automatically save a financial scenario or add balances to the address bar. Explicit local saving retains the original earlier-generation records for recovery, while sharing starts with a clean link and requires a separate choice to include financial inputs. Review that preview before copying it. Copy and CSV exports include the year roles, basis flow, assumptions and unavailable-result markers. The procedural source is final 2025 Form 8606 guidance with separately published 2026 limits; a 2026 draft exists, and this worksheet does not prepare or certify a final 2026 return.