IRS Letter 2644C: What It Means and Whether to Respond
Last updated 10/22/2026 by
SuperMoney Team
Edited by
Andrew Latham
Summary:
IRS Letter 2644C, the “Second Interim Response,” means the IRS is still working on something you sent it and could not finish by the date it gave you in an earlier interim letter. The letter must tell you why your answer is delayed and when to expect a final response. It is not a bill, an audit notice or a warning about liens or levies. In most cases you only need to keep the letter and wait for the new date.
You wrote to the IRS, maybe to answer a notice, send an amended return or ask for penalty relief. Soon after, the IRS sent an interim letter promising an answer by a certain date. That date passed, and now Letter 2644C has arrived. This article explains what the letter means, what it does not mean, and when it makes sense to follow up.
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What is IRS Letter 2644C?
Letter 2644C is the IRS’s “Second Interim Response.” IRS rules say that when the agency cannot give you a final answer within 30 days of receiving your correspondence, it must send an interim letter that promises a date. If the IRS still cannot resolve your case by that date, the Internal Revenue Manual says it must send Letter 2644C. The letter has to give the specific reason for the delay and say when the IRS expects to send its final response.
Put simply: the IRS has your paperwork, it is still working on it, and it needs more time.
Struggling with IRS notices? If you’ve received an IRS letter and aren’t sure how to handle it, you might want to explore professional tax relief options. Optima Tax Relief has helped thousands of people resolve their tax issues and get back on track with the IRS. Learn more about how they can assist you with your situation.
What Letter 2644C does not mean
- It is not a final warning. A 2644C does not mean the IRS is about to file a tax lien or levy your property.
- It is not an audit notice. If the IRS decides to examine your return, it sends a separate letter that says so.
- It is not a bill. If you owe money, that appears on a separate notice with the amount and a due date.
Pro tip
Write the new response date from your 2644C on your calendar. If that date passes with no answer, that is the time to call the IRS.
Why you might receive Letter 2644C
You only get this letter after you have contacted the IRS. Common examples include:
- You answered an IRS notice and sent supporting documents.
- You filed an amended return or a claim for a refund.
- You asked the IRS to remove a penalty.
- You asked about a payment, a refund or another item on your account.
Delays can come from case volume, from records the IRS needs to get from another unit, or from a case that needs more research. Your letter will say which reason applies to you.
What to do after receiving Letter 2644C
- Read the reason for the delay. If the letter asks you for something, such as a missing document, send it by the date shown.
- Note the new date. That is when the IRS expects to send its final response.
- Don’t resend the same documents. Duplicate submissions can slow your case down further.
- Keep copies. File the letter with the earlier interim letter and copies of everything you sent.
What if you owe the IRS money?
Letter 2644C does not ask you for money. But if the correspondence it refers to is about a balance you owe, interest generally keeps building on unpaid tax while you wait. You can pay online, set up a payment plan, or ask about other options such as an offer in compromise.
Owe the IRS more than you can pay right now? A tax relief company can help you request an installment agreement, penalty abatement or an offer in compromise. Answer a few questions to compare tax relief quotes from vetted firms, or browse tax relief companies first.
When to contact the IRS
If the date in your 2644C passes without a final response, call the number printed on the letter. Have the letter, the earlier interim letter and copies of your correspondence ready. If the delay is causing a financial hardship, for example you are waiting on a refund you need to pay bills, the Taxpayer Advocate Service may be able to help.
Frequently asked questions
Do I need to respond to IRS Letter 2644C?
Usually not. Letter 2644C is a status update. Respond only if the letter asks you for something, and send it by the date the letter gives.
What is the difference between Letter 2645C and Letter 2644C?
Letter 2645C is often the first interim letter: the IRS received your correspondence and needs more time. Letter 2644C is the second interim letter: the IRS could not finish by the date it promised, so it must explain why and give you a new date.
How long will the IRS take after sending Letter 2644C?
The letter gives you a new date. The IRS sets it based on the type of case and the office working it, so there is no standard number of days.
Does Letter 2644C mean I am being audited?
No. Letter 2644C means the IRS is still working on your correspondence. An audit starts with a separate letter that says your return has been selected for examination.
How can I tell if a Letter 2644C is real?
Check that the letter number appears on the letter and that the details match something you actually sent the IRS. You can also log in to your IRS online account, or call the IRS using a number from IRS.gov instead of a number you don’t recognize. The IRS does not demand payment by gift card or cryptocurrency.
Should I hire a tax professional to handle IRS Letter 2644C?
Usually not for the letter itself, since it only says the IRS needs more time. A professional can help if the issue behind your correspondence is complex, or if you owe more than you can pay. In that case you can compare tax relief quotes from vetted firms.
Need help understanding other IRS letters and notices? Visit our comprehensive guide to IRS Letters and Notices or search for the document you received in the table below.
| IRS Letter or Notice Number | Notice Description |
|---|---|
| CP01 | The IRS verified your claim of identity theft and will monitor your account. |
| CP01H | The IRS received a tax return with a social security number that belongs to a dead person. |
| CP02H | Money is due on an amended return based on a grant received due to Hurricane Katrina, Rita, or Wilma. |
| CP03C | You received the First-Time Homebuyer Credit for a house you purchased. |
| CP04 | You may be eligible for tax deferment because either you or a spouse served in a combat zone, a qualified contingency operation, or a hazardous duty station during the tax year specified on your notice. |
| CP08 | You may be entitled to additional money due to the Additional Child Tax Credit. |
| CP10 | Your tax return changed due to a miscalculation, and the refund you wanted to apply to an estimated tax payment has changed. |
| CP10A | Your tax return changed due to a miscalculation of the Earned Income Credit, and the refund you wanted to apply to an estimated tax payment has changed. |
| CP11 | You owe money because the IRS amended your return due to a miscalculation. |
| CP11A | Your tax return changed due to a miscalculation of the Earned Income Credit, and the refund you wanted to apply to an estimated tax payment also changed. |
| CP11M | Your tax return changed due to a miscalculation of the Making Work Pay and Government Retiree Credit, and the refund you wanted to apply to an estimated tax payment has changed. |
| CP12 | You are due a bigger refund because the IRS corrected one or more mistakes on your tax return. |
| CP12A | The IRS made changes to correct the Earned Income Credit (EIC) claimed on your tax return. |
| CP12E or CP12F | The IRS corrected a miscalculation on your return. |
| CP12M | The IRS made changes to the computation of the Making Work Pay and/or Government Retiree Credits on your return. |
| CP12R | The IRS made changes to the computation of the Rebate Recovery Credit on your return. |
| CP13 | The IRS made changes to your return due to a miscalculation. There is no refund or amount due. Your balance is zero. |
| CP13A | The IRS made changes to your return due to a miscalculation of the Earned Income Credit. There is no refund or amount due. Your balance is zero. |
| CP13M | The IRS made changes to your return due to a miscalculation of the Making Work Pay credit or the Government Retiree Credit. There is no refund or amount due. Your balance is zero. |
| CP13R | The IRS made changes to your return due to a miscalculation of the Recovery Rebate Credit. There is no refund or amount due. Your balance is zero. |
| CP14 | You owe money on unpaid taxes. |
| CP16 | The IRS made changes to your return due to a miscalculation. The refund you were due was applied to other tax debts. |
| CP21A | You owe money due to the changes you requested that the IRS make on your tax returns. |
| CP21B | You are due a refund due to the changes you requested that the IRS make on your tax returns. The money should arrive within 2 to 3 weeks. |
| CP21C | The IRS made the requested changes to your tax return. You will not receive a refund, and there is no tax due. Your balance is zero. |
| CP21E | As a result of your recent audit, the IRS made changes to your tax return, and you owe money as a result of those changes. |
| CP21I | The IRS made changes to your tax return relating to the Individual Retirement Arrangement (IRA) taxes. You owe money due to the changes. |
| CP22A | The IRS made the changes you requested, and you owe money as a result. |
| CP22E | As a result of your recent audit, the IRS changed your tax return, and you now owe money. |
| CP22I | The IRS made changes to your tax return relating to the Individual Retirement Arrangement (IRA) taxes. You owe money due to the changes. |
| CP23 | The IRS changed your return because there was a difference between the amount of estimated tax payments listed on your tax return and the amount actually posted to your account. You owe taxes due to these changes. |
| CP24 | The IRS changed your return because there was a difference between the amount of estimated tax payments listed on your tax return and the amount actually posted to your account. This resulted in an overpayment of estimated taxes. |
| CP24E | The IRS changed your return because there was a difference between the amount of estimated tax payments listed on your tax return and the amount actually posted to your account. This resulted in an overpayment of estimated taxes. |
| CP25 | The IRS changed your return because there was a difference between the amount of estimated tax payments listed on your tax return and the amount actually posted to your account. You are not due a refund, nor do you owe any money. Your balance is zero. |
| CP31 | You need to update your address because your refund check was returned to the IRS. |
| CP45 | The IRS was unable to apply your overpayment to your estimated tax as you requested. |
| CP49 | The IRS used all or part of your refund to pay a tax debt. |
| CP53 | Your refund check will be sent by mail because the IRS can’t provide your refund through direct deposit. |
| CP57 | The bank declined your payment, so the IRS was unable to draft funds from your bank account. |
| CP71 | A reminder of the amount you owe in tax, penalty, and interest. |
| CP71A | A reminder of the amount you owe in tax, penalty, and interest. |
| CP71C | A reminder of the amount you owe in tax, penalty, and interest. |
| CP71D | A reminder of the amount you owe in tax, penalty, and interest. |
| CP88 | The IRS is holding your refund because you haven't filed one or more tax returns, and it believes you will owe tax. |
| CP90 | The IRS is notifying you of its intent to levy certain assets for unpaid taxes. You have the right to dispute the levy in a Collection Due Process hearing. |
| CP91 | The IRS will levy up to 15% of your social security benefits for unpaid taxes. |
| CP120 | The IRS needs documentation of your tax-exempt status. |
| CP120A | Your organization’s tax-exempt status has been revoked because it failed to file a Form 990 series return for three consecutive years. |
| CP130 | You may no longer need to pay the Alternative Minimum Tax (AMT) because your tax return filing requirements changed. |
| CP152 | The IRS received your return. |
| CP153 | The IRS will send your refund by mail because your direct deposit did not go through. |
| CP161 | You have an unpaid balance due to the IRS. |
| CP166 | Your monthly payment to the IRS did not go through due to insufficient funds in your bank account. |
| CP178 | You may no longer owe excise tax because your tax return filing requirements changed. |
| CP231 | You need to update your address because your refund was returned to the IRS. |
| CP259 | You did not file the business tax return identified in the notice. |
| CP259A | You should have filed these forms but did not – Form 990/990-EZ, Return of Organization Exempt From Income Tax, or Form 990-N (e-Postcard). |
| CP259B | The IRS requires you to file these forms but did not – Form 990-PF, Return of Private Foundation or Section 4947(a)(1) Nonexempt Charitable Trust Treated as a Private Foundation. |
| CP259C | The IRS believes that you are a private foundation, but did not file the required Form 990-PF, Return of Private Foundation or Section 4947(a)(1) Nonexempt Charitable Trust Treated as a Private Foundation. |
| CP259D | You must file this form, but you did not – Form 990-T, Exempt Organization Business Income Tax Return. |
| CP259E | You should have filed this form, but you did not – Form 990-N (e-Postcard) or Form 990/990-EZ, Return of Organization Exempt From Income Tax. |
| CP259F | The IRS requires you to file this form but did not – Form 5227, Split-Interest Trust Information Return. |
| CP259G | The IRS requires you to file this form, but you didn’t – Form 1120-POL, U.S. Income Tax Return for Certain Political Organizations. |
| CP259H | As a tax-exempt political organization, you must file this form, but you did not – Form 990/990-EZ, Return of Organization Exempt From Income Tax. |
| CP276A | You submitted your tax liability schedule incorrectly. The IRS typically charges a Federal Tax Deposit (FTD) penalty for this but did not this time. |
| CP276B | The IRS did not receive the correct amount of tax deposits. It normally charges a Federal Tax Deposit (FTD) penalty but did not this time. |
| CP297 | The IRS is notifying you of its intent to levy certain assets for unpaid taxes. You have the right to dispute the levy at a Collection Due Process hearing. |
| CP297A | The IRS has levied your assets for unpaid taxes. You have the right to dispute the levy at a Collection Due Process hearing. |
| CP298 | The IRS notifying you of its intent to levy up to 15% of your social security benefits for unpaid taxes. |
| CP501 | You have a balance due on one of your tax accounts. |
| CP503 | You have an unpaid balance on one of your accounts, and the IRS has not heard from you. |
| CP504 | You have an unpaid amount due on your account. If you do not pay immediately, the IRS will levy your state income tax refund to apply it to the amount you owe. |
| CP504B | You have an unpaid amount due on your account. If you do not pay immediately, the IRS will levy certain property or rights to property to apply it to the amount you owe. |
| CP521 | A reminder that you have an installment agreement payment due. |
| CP523 | You have defaulted on your payment agreement. Therefore the IRS is terminating the agreement and will levy your assets. |
| CP601 | Usted tiene un saldo pendiente de pago (dinero que le debe al IRS) en una de sus cuentas contributivas. |
| CP603 | No hemos recibido respuesta de parte de usted y todavía tiene un saldo sin pagar en una de sus cuentas contributivas. |
| CP604 | Usted tiene un saldo sin pagar en su cuenta. De no pagar esta cantidad inmediatemente, el IRS embargará cualquier reembolso de impuestos estatales al que tenga derecho y aplicarlo al pago de su deuda. |
| CP604B | Usted tiene un saldo sin pagar en su cuenta. De no pagar esta cantidad inmediatemente, el IRS embargará ciertas propiedades o derechos de propiedad y lo aplicará al pago de su deuda. |
| CP621 | Este aviso es para notificarle que usted tiene un plan de pagos a plazos vencido. Por favor, envíe el pago inmediatamente. |
| CP623 | Este aviso es para informarle nuestra intención de cancelar su plan de pagos a plazos y confiscar (embargar) sus bienes. Usted incumplió en su acuerdo. |
| CP711 | Nosotros realizamos cambios a su planilla debido a que entendemos que hubo un cálculo erróneo. Como resultado de estos cambios, usted adeuda dinero por sus contribuciones. |
| CP721 | Hicimos el(los) cambio(s) que usted solicitó a su declaración de impuestos para el año tributario que aparece en su aviso. Como resultado de éste(estos) cambio(s) usted debe dinero en sus impuestos. |
| CP722 | Hicimos el(los) cambio(s) que usted solicitó a su declaración de impuestos para el año tributario que aparece en su aviso. Como resultado de éste(estos) cambio(s) usted debe dinero en sus impuestos. |
| CP771 | Usted recibió este aviso para recordarle sobre la cantidad que adeuda en contribuciones, multas e intereses. |
| CP772 | Usted recibió este aviso para recordarle sobre la cantidad que adeuda en contribuciones, multas e intereses. |
| CP773 | Usted recibió este aviso para recordarle sobre la cantidad que adeuda en contribuciones, multas e intereses. |
| CP774 | Usted recibió este aviso para recordarle sobre la cantidad que adeuda en contribuciones, multas e intereses. |
| CP959 | Usted no radicó su planilla de contribución de negocios identificada en este aviso. |
| CP2000 | The income or payment information on file doesn’t match your tax return. The discrepancy may result in an increase or decrease in your tax due. |
| CP3219A | The IRS has received information that is different from what you reported on your tax return. This may result in an increase or decrease in your tax. |
| CP3219N | The IRS didn’t receive your tax return, so it calculated your return based on the information received from employers, financial institutions, and others. If you want to challenge the proposed tax, you have 90 days from the date of this notice. If you are outside the country, you have 150 days. |
| Letter 0012C | The IRS needs additional information to process your tax return. |
| Letter 0484C | The IRS wants a completed |
| Letter 0525 | Updates you on proposed changes after an IRS examination. Any changes are explained and details the refund due or taxes owed. |
| Letter 531 | IRS Notice of Deficiency. The information the IRS received about you was different from what you reported on your return. |
| Letter 0668D(LP 68) | The IRS released their levy. |
| Letter 0549C | Your tax bill was paid. |
| Letter 0681C | The IRS accepted your payment proposal. However, this is not a formal Installment Agreement. |
| Letter 0757C | You did not adhere to the terms of your Installment Agreement. |
| Letter LT 11 | The IRS plans to seize your property or rights to property. |
| Letter 1058 | The IRS has not received your payment. It plans to seize your property or rights to property. |
| Letter 1615 (LT 18) | You must respond to the IRS within 10 days of this notice regarding past due tax returns. |
| Letter 1737 (LT 27) | Complete and sign Form 433F, Collection Information Statement. |
| Letter 1961C | Your application for a Direct Debit Installment Agreement was declined. It explains why and what you need to do to qualify. |
| Letter 1962C | Your application for a |
| Letter 2050 (LT 16) | The IRS is trying to collect unpaid taxes from you from returns that have been filed or from returns that have not been filed. |
| Letter 2257C | The IRS is providing the payoff amount that you requested. |
| Letter 226-J | An IRS letter to large employers notifying them that they may be liable for an Employer Shared Responsibility Payment (ESRP). |
| Letter 2271C | A request for an Installment Agreement has been approved. It explains the fees and how to qualify for a Low Income Fee Reduction. The letter may also request missing information. |
| Letter 2272C | An IRS letter explaining why your request to pay the balance due in installments was declined. |
| Letter 2273C | A confirmation letter of your request to pay the balance due in installments. It contained the amount to pay, fees charged, and where to send payment. Instructions on how to apply for the Low Income Fee Reduction included. |
| Letter 2318C | A response to a request to pay taxes due to payroll deductions. It also explains the fees that are charged. |
| Letter 2357C | The IRS is admitting that it did not send you the balance due notices that it should have. |
| Letter 2603C | The IRS accepted your installment agreement. The IRS will file a Notice of Federal Tax Lien on your personal property. |
| Letter 2604C | The IRS has accepted your request for installment payments. This IRS letter provides the monthly payment, the address where to send it, and the fees charged. The letter also provides instructions on how to apply for the Low Income Fee Reduction. |
| Letter 2761C | The IRS is requesting your combat zone service dates to ensure that it provides you with the special provisions and protection of the combat zone deferment. Copies of military orders or other documentation to support your time served may be requested. Civilians working in support of the Armed Forces may be required to provide a Letter of Authorization or a letter from their employer. |
| Letter 2789C | An annual reminder notice, as required by law, of the balance due to the IRS. It explains that penalties and interest continue to accrue until the balance is fully paid. |
| Letter 2840C | Confirms your Installment Agreement request and includes the payment amount and due date. This IRS letter explains the fees charged for paying monthly and explains how to apply for the Low Income Fee Reduction (if you qualify). |
| Letter 3030C | Provides an explanation of the tax, penalty, and interest still due on your account. |
| Letter 3127C | A confirmation of your request to make a change to your Installment Agreement. This IRS letter explains the fees for the change. Changes can be to the payment amount or due date, or it can include additional liabilities. |
| Letter 3174 | A reminder of taxes due after the IRS has sent a Notice of Intent to Levy. |
| Letter 3217C | The IRS has accepted your request to pay the balance in installments. This IRS letter provides your payment amount, the due date, and fees charged. The letter also provides instructions on applying for the Low Income Fee Reduction (if you qualify). |
| Letter 3228 (LT 39) | A request to pay the balance due within 10 days using the envelope provided. |
| Letter 3500 | The IRS has received your documents, and it needs additional time to review them. |
| Letter 3572 | Your Federal Income Tax Return has been selected for examination. The IRS auditor requests that you call to schedule an audit appointment. |
| Letter 4883C | The IRS received your federal income tax return but needs more information to verify your identity in order to process your tax return accurately. |
| Letter 4903 (LT 26) | You must file your tax returns immediately. The IRS has previously contacted you, but it did not receive a response. |
| Letter LP 47 | The IRS is trying to locate the person identified in the letter and is requesting that you provide their new address. |
| Letter LP 59 | The IRS has not received a response to the notice of levy it previously sent. |
| Audit Letter 2205 | The IRS manages audits either by mail or through an in-person interview to review your records. The interview may be at an IRS office (office audit) or the taxpayer’s home, place of business, or accountant’s office (field audit). |
| Letter 915 | You recently underwent an audit, and the IRS informs you that you now owe taxes. |
Don't see your notice? Browse all 946 IRS notices and letters we explain
Key takeaways
- IRS Letter 2644C is the IRS’s second interim response: it still needs more time on your correspondence.
- The letter must explain the reason for the delay and give a new date for a final answer.
- It is not a final warning, a bill or an audit notice, and it does not mean a lien or levy is coming.
- You usually don’t need to respond unless the letter asks you for something.
- If the new date passes with no answer, call the number on the letter.
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