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After-Tax Basis

Money in a traditional IRA that has already been taxed.

After-tax basis generally refers to nondeductible money in a traditional IRA that has already been taxed. Basis can reduce the taxable portion of a Roth conversion, but it must be tracked carefully and is commonly reported using Form 8606.

Related terms

Pro-Rata RuleForm 8606Taxable Conversion

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Open the Roth Conversion Calculator to see how this term appears in educational scenario modeling.

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This Roth Conversion Calculator is for educational and illustrative purposes only. It does NOT constitute tax, financial, legal, or investment advice. The calculation results are based on the information you provide and the latest IRS tax rules, which are subject to change. We do not guarantee the accuracy of the results. Please consult a licensed Certified Public Accountant (CPA), financial advisor, or tax professional before making any financial decisions.