Source Registry
Every law, manual section, and administrative ruling used to build the guides and calculators on this site. Updated for 2026.
Internal Revenue Code (IRC)
Primary federal tax statutes enacted by Congress. These are the laws — the IRS cannot override them.
| Source | Official Title | Link |
|---|---|---|
| IRC § 6502 | Collection After Assessment — Length of Period of Collection Defines the 10-year Collection Statute Expiration Date (CSED) on all federal tax debt. | .gov |
| IRC § 6321 | Lien for Taxes Establishes the statutory basis for the creation of federal tax liens upon failure to pay after demand. | .gov |
| IRC § 6330 | Notice and Opportunity for Hearing Before Levy Grants taxpayers the right to a Collection Due Process (CDP) hearing before the IRS can levy property. | .gov |
| IRC § 6343 | Authority to Release Levy and Return Property Defines the conditions under which the IRS must release an active levy, including economic hardship and installment agreements. | .gov |
| IRC § 6672 | Failure to Collect and Pay Over Tax Establishes personal liability (Trust Fund Recovery Penalty) for responsible persons who willfully fail to remit payroll trust fund taxes. | .gov |
| IRC § 7122 | Compromises Grants the IRS authority to settle tax debts for less than the full amount owed — the legal basis for the Offer in Compromise program. | .gov |
| IRC § 6159 | Agreements for Payment of Tax Liability in Installments Authorizes installment agreements and defines the IRS's authority to modify or terminate them. | .gov |
| IRC § 6015 | Relief from Joint and Several Liability on Joint Return Defines the three forms of Innocent Spouse Relief available to taxpayers jointly liable for a spouse's tax errors. | .gov |
| IRC § 6212 | Notice of Deficiency Governs the issuance of Notices of Deficiency and establishes the 90-day window to petition the U.S. Tax Court. | .gov |
Internal Revenue Manual (IRM)
The IRS's internal procedural manual. These are the rules IRS employees must follow when administering the law.
| Source | Official Title | Link |
|---|---|---|
| IRM 5.15.1 | Financial Analysis Handbook Defines Allowable Expenses, Quick Sale Value methodology, and RCP calculation procedures used in our OIC Calculator. | .gov |
| IRM 5.8.1 | Offer in Compromise Overview Procedural rules for OIC submission evaluation, acceptance criteria, and rejection standards. | .gov |
| IRM 8.25.1 | Trust Fund Recovery Penalty Defines the TFRP assessment process, responsible person interviews (Form 4180), and penalty contestation procedures. | .gov |
| IRM 5.12.1 | Federal Tax Liens Standardized protocols for NFTL filing, lien discharge, subordination, withdrawal, and release procedures. | .gov |
| IRM 5.14.1 | Statute of Limitations Governs CSED computation, tolling event identification, and statute verification procedures. | .gov |
| IRM 5.16.1 | Currently Not Collectible Defines CNC status criteria, financial analysis requirements, and account monitoring procedures. | .gov |
| IRM 8.23.1 | Collection Appeals Program Procedures for the Collection Appeals Program (CAP), including eligibility, timelines, and limitations. | .gov |
| IRM 20.1.1 | Penalty Handbook — Failure to File / Pay Defines failure-to-file and failure-to-pay penalty rates, First-Time Abatement criteria, and reasonable cause standards. | .gov |
Public Laws — OBBBA (P.L. 119-21)
Specific provisions of the One Big Beautiful Bill Act affecting tax resolution calculations in 2026.
| Source | Official Title | Link |
|---|---|---|
| P.L. 119-21, § 101 | Qualified Overtime Deduction (OBBBA) Establishes the above-the-line deduction for qualified overtime pay ($12,500 single / $25,000 joint) reducing Monthly Disposable Income in OIC calculations. | .gov |
| P.L. 119-21, § 203 | 1099-NEC Reporting Threshold Adjustment (OBBBA) Raises the Form 1099-NEC reporting threshold from $600 to $2,000 for payments to non-employees, effective tax year 2026. | .gov |
Revenue Rulings & Administrative Notices
Real-time IRS guidance on rates, thresholds, and procedural changes. Updated as new rulings are published.
| Source | Official Title | Link |
|---|---|---|
| Rev. Rul. 2026-5 | Q2 2026 Federal Interest Rates Sets the underpayment interest rate at 6% (annual) for Q2 2026 (April 1 – June 30). Used in all daily interest accrual calculations on this site. | .gov |
| IR-2026 (Pending) | 2026 Collection Financial Standards Postponement IRS announcement delaying the annual update to Collection Financial Standards from April 1 to June 1, 2026. All calculators use the current transitional data. | .gov |