Federal tax source updates
This is a source map, not a prediction of future rules. TaxBreakTools keeps 2025 return calculations separate from 2026 planning figures and links to the controlling IRS form or instructions whenever possible.
Source map reviewed .
2025 returns
Schedule 1-A and its worksheets
Official form and worksheets for the qualified-tips, qualified-overtime, car-loan-interest, and enhanced-senior deductions.
Open 2025 Schedule 1-A (opens in a new tab)2025 returns
Schedule A instructions
Official itemized-deduction instructions, including the 2025 state-and-local-tax limitation and worksheet.
Open 2025 Schedule A instructions (opens in a new tab)2025 returns
Schedule SE instructions
Official rules for figuring self-employment tax and the deductible employer-equivalent portion.
Open 2025 Schedule SE instructions (opens in a new tab)2025 returns
Form 1040 instructions
The return-level source needed to place a narrow calculator result in the context of income, deductions, credits, other taxes, and payments.
Open Form 1040 instructions (opens in a new tab)2026 planning
IRS inflation adjustments for tax year 2026
Official 2026 standard deductions, bracket thresholds, and other inflation-adjusted federal figures. These are not substituted into 2025-only Schedule 1-A or Schedule A tools.
Open the IRS 2026 adjustments (opens in a new tab)Current IRS overview
Working Families Tax Cuts
IRS overview and implementation links for individual provisions enacted in 2025. Use the linked form or instructions for an actual return.
Open the IRS overview (opens in a new tab)How changes are handled
A newer IRS revision does not automatically make an older-year calculator wrong, and a planning announcement does not replace return instructions. Supported formulas are versioned by tax year, reviewed against the linked primary source, and narrowed or retired when the site cannot model the rule responsibly.