2026 Backdoor Roth Calculator

Background.

2026 Backdoor Roth Calculator supports a concrete decision: use it to apply Form 8606 aggregation and the pro-rata rule to a nondeductible IRA conversion. The result needs one precise interpretation: the pro-rata fraction uses total basis over the year-end value of all traditional, SEP and SIMPLE IRAs plus distributions and conversions. The selected relationship is “nontaxable conversion = conversion × nondeductible basis ÷ total year-end IRA balance; taxable conversion is the remainder.”

The editable entries are amount converted to roth, total nondeductible ira basis, pretax balance across traditional, sep and simple iras. Use values from the document or measurement that governs this 2026 backdoor roth question; the defaults are only the worked fixture below. Looking only at the newly opened IRA is the common error; employer-plan balances are treated differently and are not entered here. The 2026 backdoor roth calculation does not infer that fact from the other entries.

IRS Instructions for Form 8606; aggregation and pro-rata treatment of nondeductible IRA basis documents the convention or governing rule used here. The 2026 backdoor roth output is a transparent scenario under those facts: it does not manufacture an unentered market price, professional determination, carrier quote, legal eligibility finding or locally adopted code value.

What is 2026 backdoor roth calculator?

2026 Backdoor Roth is the relationship behind this decision: the pro-rata fraction uses total basis over the year-end value of all traditional, SEP and SIMPLE IRAs plus distributions and conversions. On this page it means nontaxable conversion = conversion × nondeductible basis ÷ total year-end IRA balance; taxable conversion is the remainder. Looking only at the newly opened IRA is the common error; employer-plan balances are treated differently and are not entered here; that is the line between the reported quantity and a broader retirement analysis.

How to use this calculator.

1. 01Confirm that “nontaxable conversion = conversion × nondeductible basis ÷ total year-end IRA balance; taxable conversion is the remainder” matches the 2026 backdoor roth convention you need.
2. 02Replace the fixture values for amount converted to roth, total nondeductible ira basis, pretax balance across traditional, sep and simple iras with dated values from the governing record.
3. 03Keep all currencies, measurement units and time periods on the same basis before calculating.
4. 04Read estimated taxable conversion together with this boundary: Looking only at the newly opened IRA is the common error; employer-plan balances are treated differently and are not entered here.

The formula.

The calculation uses nontaxable conversion = conversion × nondeductible basis ÷ total year-end IRA balance; taxable conversion is the remainder. In this 2026 backdoor roth model, the entered terms are amount converted to roth, total nondeductible ira basis, pretax balance across traditional, sep and simple iras. The pro-rata fraction uses total basis over the year-end value of all traditional, SEP and SIMPLE IRAs plus distributions and conversions, which is why the relationship is presented under this name rather than as a universal alternative. Looking only at the newly opened IRA is the common error; employer-plan balances are treated differently and are not entered here. Calculations keep full decimal precision through the relationship and round only the returned display values.

A worked example.

Frequently asked questions.

References& sources.

1. [1]IRS Instructions for Form 8606; aggregation and pro-rata treatment of nondeductible IRA basis. Retrieved 2026-08-07. access: open unless marked otherwise.
2. [2]IRS Publication 590-A, Contributions to Individual Retirement Arrangements; IRA contribution and conversion basis rules. Retrieved 2026-08-07. access: open unless marked otherwise.
3. [3]U.S. Internal Revenue Service. About Form 8606, Nondeductible IRAs. Retrieved 2026-08-07. independence: primary; access: open.
4. [4]U.S. Internal Revenue Service. Publication 590-B, Distributions from Individual Retirement Arrangements. Retrieved 2026-08-07. independence: primary; access: open.
5. [5]U.S. Internal Revenue Service. Retirement topics — IRA contribution limits. Retrieved 2026-08-07. independence: primary; access: open.