How the IRS works: a subway map of the taxpayer's journey

W-2s, 1099s, bank interest, ITIN/SSN for everyone on the return. The more complete the set, the fewer IRS letters later.

Decision point: self-service software or a professional. Mistakes here are the main source of every other line on this map.

The self-employed and LLC owners pay tax four times a year (Form 1040-ES). Underpaying estimates means a penalty even if the return itself is perfect.

E-filing beats paper: the IRS confirms receipt within 24–48 hours and nothing gets lost in the mail.

Can't make April 15? Form 4868 automatically extends filing to October 15 — but the tax itself is still due in April.

The return passed the initial filters and is in processing. A typical e-file with direct deposit: refund within 21 days.

If the return looks like it might be fraudulent, the IRS freezes it and sends Letter 5071C: confirm it was really you.

The IRS found a math error and recalculated the return itself. The letter says the result: you owe (CP 11), refund (CP 12) or zero (CP 13).

The refund is approved and on its way. Track it in Where's My Refund — you need SSN/ITIN, filing status and the exact refund amount.

CP 05: the return was pulled for review — wait up to 60 days; calling earlier won't help. If you didn't file that return, it's an identity-theft signal.

The refund didn't vanish — the IRS applied it to an old tax debt of yours. Anything left over still gets sent to you.

The return shows tax due and no payment arrived. This is the transfer to the red line: the first bill, CP 14, is already on its way.

The return got picked: at random, because it doesn't match employer/bank data, or because credits and deductions look unusually large.

Over 90% of exams happen by mail (correspondence exam). Office and field exams are rarer and more serious — bring a representative.

CP 2000: third-party data doesn't match the return — it's a proposal, not a final bill. CP 75: prove your credits with documents; the refund is frozen meanwhile.

Usually 30–60 days to send documents and disagreements. Silence is treated as agreeing with the proposed assessment.

The Notice of Deficiency — the IRS's final word. Exactly 90 days to petition the Tax Court; after that the amount becomes assessed debt.

Agree — sign and pay (or set up a payment plan). Disagree — Appeals (the purple line) or court (the blue line).

The first bill: you owe, usually 21 days to pay. Interest is already running.

The reminder wave. The balance grows every month: failure-to-pay penalty plus interest.

The Notice of Intent to Levy: the IRS can take your state tax refund and is preparing a levy.

The final warning: 30 days before a levy. Form 12153 for a CDP hearing freezes collection while it's pending.

Special collection routes: CP 90 — the final notice with CDP hearing rights; CP 91 — the IRS is about to take up to 15% of Social Security benefits.

Bank levy, wage garnishment, a federal tax lien. From here the IRS takes money with no further warnings — until the debt is gone.

You can exit the red line at any station: an Installment Agreement, an Offer in Compromise — part of the debt gets written off, or Currently Not Collectible — collection goes on pause. The earlier, the cheaper.

After disagreeing with an exam — a written protest. After LT 11 or CP 90 — Form 12153 for a Collection Due Process hearing: collection pauses while it's pending.

The fast track for disputing collection actions (levy, lien, terminated payment plans): a decision in days, not months. The catch — a CAP decision can't be taken to court afterwards.

An informal phone or video conference with an appeals officer — no judge, no transcripts. You can bring a representative (EA, CPA, attorney).

Appeals weighs the hazard that the IRS loses in court — which is why it can settle for amounts the exam team never could.

The appeals decision. Agree — end of the line. Disagree — the blue line remains: court.

The only court you can go to BEFORE paying the debt. The 90-day deadline is unforgiving: one day late and the petition is rejected. Disputes up to $50,000 qualify for the simplified S-case procedure.

The alternative route: pay the debt first, then sue for a refund in federal district court or the Court of Federal Claims.

Most cases never reach trial: IRS counsel prefers to settle. If yours does, a Tax Court judge decides on the merits.

A Tax Court decision can be appealed to your circuit's federal appeals court. Beyond that lies the Supreme Court — which takes a handful of tax cases at best.