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Tax · United States

IRS Notice CP161 — an unpaid balance notice for your business

A CP161 is the business version of a balance-due bill: IRS records show a business — or business-type taxes such as employment or excise taxes — carries an unpaid balance. It breaks the amount into tax, penalties and interest, and asks for payment by a due date.

How serious: needs actionAlso called: CP161, business balance due notice

The CP161 is the business equivalent of a balance-due bill. The IRS's records show your business (or you, for business-type taxes such as employment or excise taxes) has an unpaid balance.

The notice explains how the amount was calculated — tax, penalties and interest — and requests payment by a due date. It is addressed to a business name and/or an EIN.

It is common for owners of small businesses and for self-employed visa holders. Even when it concerns an individual, the taxes involved are business-type ones.

Who sends it

The Internal Revenue Service (IRS) — the United States federal tax authority, part of the Department of the Treasury.

The code 'CP161' is printed in the top corner, and the notice is addressed to a business name and/or EIN. The wording runs 'You have an unpaid balance due', with a breakdown of tax, penalty and interest, and the line 'Contact us within 10 days of the date of your notice if you think we made a mistake'.

The deadline

Pay the amount due by the date on the notice; 'Contact us within 10 days of the date of your notice if you think we made a mistake' (IRS CP161 page)

Payment is due by the date printed on the notice. For disputes, the notice itself says to contact the IRS within 10 days of its date if you think a mistake was made.

If you do nothing

Interest continues to increase on the unpaid balance after the payment due date, and a late-payment or failure-to-deposit penalty applies. Further collection follows the process described in Publication 594 (The IRS Collection Process) — escalating notices, lien and levy.

How it escalates

  1. 01Interest keeps growing, and late-payment or failure-to-deposit penalties apply.
  2. 02Additional collection notices follow, per Publication 594, leading to a Notice of Federal Tax Lien and notices of intent to levy.
  3. 03Eventually, levy of business bank accounts, receivables and assets — after a final CDP notice.

Your options, procedurally

  • The amount due can be paid by the date on the notice.
  • A payment plan can be requested if the business cannot pay in full.
  • The IRS can be contacted within 10 days, with documentation, if the notice is believed to be wrong.
  • Form 2848 can be filed to authorize a representative (an accountant or attorney).

Common questions

Is the CP161 about me personally or about the business?

It is addressed to a business name and/or EIN and concerns business-type taxes, such as employment or excise taxes — which can also apply to an individual who owes those kinds of taxes.

What if the notice looks wrong?

The notice itself says to contact the IRS within 10 days of its date if you think a mistake was made. Documentation can be provided to support the dispute.

What happens if the balance goes unpaid?

Interest keeps increasing and a late-payment or failure-to-deposit penalty applies. Collection then escalates per Publication 594 — further notices, a Notice of Federal Tax Lien, intent-to-levy notices, and eventually levy of business bank accounts, receivables and assets after a final CDP notice.

Sources

Facts verified against the sources below on 28 August 2026.