A basis ledger helps organize what you know and what still needs evidence. It should reconcile with your filed records rather than replace them.
2025 standard rules · 2026 form projections
Use one ledger per person
Add a row for each year and record opening basis, nondeductible additions, basis used and ending basis. Annotate any correction instead of silently overwriting history.
Verify the opening balance
If your historical basis is uncertain, mark it unresolved. The tool's arithmetic cannot reconstruct missing filings or prove that a contribution was nondeductible.
Attach a reference to the year's filed form in your own records.
Keep contribution confirmations and relevant rollover documentation.
Review unusual basis adjustments with a professional.
Sources and next steps
Reviewed October 10, 2026. This independent educational website is not affiliated with the IRS. Special transactions need professional review.