U.S. · IRS letters
IRS Letter 4800C explained.
A letter proposing a change to your tax return.
Letter 4800C tells you the IRS is proposing a change to your tax return. The IRS page says to review the “Changes to Your Return” section, decide whether you agree, and complete and return the Response Form within 30 days from the date of the letter.
Compare IRS letters and notices
Result
IRS letters and notices at a glance
| Letter or notice | What the IRS page says it is | Response, as the IRS page states it |
|---|---|---|
| Letter 12C | The IRS needs more information to process your individual income tax return: missing or corrected forms or schedules, verification of income, withholding and credit amounts, or verification of taxpayer identification numbers or Social Security numbers. | Send the information requested within 20 days. Respond even if you disagree, with a clear explanation. Do not file Form 1040-X. |
| Letter 4464C | Verifying your income and income tax withholding on a return. | If you filed a return, no action is needed. Do not call until 60 days after the letter date, and only if you have not received your refund or heard from the IRS by then. |
| Letter 4800C | The IRS is proposing a change to your tax return. | Complete and return the Response Form within 30 days from the date of the letter. If you disagree, reply with supporting documentation. |
| Letter 4883C | The IRS received a Form 1040-series return filed under your SSN or ITIN and needs you to verify your identity and the return to continue processing it; if you didn’t file one, you must let the IRS know. | Call the Taxpayer Protection Program Hotline shown in your letter immediately, with the listed documents on hand. The page prints no number of days. |
| CP5447 series (including 5447C) | A Form 1040-series return was filed under your SSN or ITIN, and the IRS needs you to verify your identity and the return. | Verify your identity and the return. If you can’t verify online, verify by phone, by mail or with the Document Upload Tool as your notice instructs. The page prints no number of days. |
| Letter 5747C | The IRS received a Form 1040-series return under your SSN or ITIN and needs to verify your identity and the return; you may need to visit a Taxpayer Assistance Center. | Act immediately. If you didn’t file, call the Taxpayer Protection Program hotline on your letter. If you did file, call the Taxpayer Assistance Center number on your letter to schedule an in-person appointment. The page prints no number of days. |
| Letter 6419 | Advance Child Tax Credit Reconciliation: the total of 2021 advance CTC payments and the number of qualifying children used to calculate them. | No response is requested. Families who received advance payments must file a 2021 return and compare the payments received with the CTC they can claim. Keep the letter with your tax records. |
| Letter 6475 | Economic Impact Payment (EIP) 3 End of Year: the total third Economic Impact Payment and any plus-up payments received for tax year 2021. | No response is requested. The letter helps determine whether you are eligible to claim the Recovery Rebate Credit on your 2021 return. |
| LT16 notice | The IRS is trying to collect unpaid taxes and/or its files show you are missing tax returns. | Read the notice and follow its instructions. File any missing returns, pay the balance, or pay what you can and set up an installment agreement. The page prints no number of days. |
| Letter 2800C | The IRS believes your employee may have filed an incorrect Form W-4, Employee’s Withholding Certificate. | Begin withholding income tax from the employee’s wages at the rates in the letter, effective 60 days from the date of the letter. Contact details are on the IRS page and the letter. |
| LT11 notice | The IRS hasn’t received your payment for overdue taxes and intends to seize your property or rights to property. You must contact the IRS immediately. | Contact the IRS immediately. Pay the unpaid balance, pay what you can, or request an installment agreement. To appeal the proposed levy, follow the instructions on the letter. The IRS page prints no number of days. |
| LT38 notice | An update on your outstanding balance because some collection notices were suspended during the pandemic and normal operations are resuming. It isn’t an audit. | Read the notice and follow its instructions. File any missing returns and pay the unpaid balance; if you can’t pay in full, see the page’s options. The page prints no number of days. |
| LT39 notice | A written reminder, required by law, about your overdue balance and any missing returns. | Pay the balance due on or before the due date on the notice. File any missing returns. If you’ve already paid, call the number on the notice. |
| Letter 2531 | Information reported on your tax return doesn’t match information reported to the IRS by third parties. The response form named on the page is for business (BMF) income tax returns. | Complete and return response Form 15114 by the date shown on the letter, saying whether you agree or disagree. If you disagree, attach a signed statement explaining each item. |
| Letter 4310C | Someone may have attempted to impersonate you using your name and Social Security number; the IRS says it resolved the issue through processing safeguards and flagged your account. | If you already filed the return for the year on the letter, submit nothing. If you haven’t, file a paper return by mail to the Submission Processing Campus for your state. Follow the letter’s instructions. |
The letter or notice number is printed on the document itself. Use it exactly as printed; the table follows the IRS page for each number. Where a response time is not printed on the IRS page, the table says so and the date on your own letter controls.
What the IRS page says the letter is
The page’s one-line description is “We’re proposing a change to your tax return.” Its FAQ says the IRS selects some returns to determine whether income, expenses and credits are being reported accurately, and that this doesn’t mean you made an error or were dishonest.
What the IRS page asks you to do
Review your tax return for the tax year in question. Review the “Changes to Your Return” section of the letter to decide whether you agree or disagree. If you don’t agree, reply with supporting documentation; the page says a list of supporting items is in the letter. Complete and return the Response Form within 30 days from the date of the letter.
Where to respond
The page calls the Documentation Upload Tool the fastest way: complete your letter (signed and dated), scan or photograph it showing whether you agree or disagree, complete the upload form and submit. You can also fax to the number in the letter (the page warns you to understand an online fax service’s privacy and security policies) or mail in the envelope enclosed with the letter.
If you don’t respond, and after you respond
The page says that if you don’t respond, the IRS will send a notice requesting additional documents or an explanation of adjustments it made to your tax, withholding and credits. After you respond, it says the IRS will contact you within 180 days if it has questions, and that it takes about 9 weeks to review your response and make changes.
If you didn’t file the return
The page says someone else may have filed it without your consent and to send a completed and signed Form 14039, Identity Theft Affidavit.
More IRS letter pages
Other pages in this set: Letter 12C, Letter 4464C, Letter 4883C, CP5447 series, Letter 5747C, Letter 6419, Letter 6475, LT16 notice, Letter 2800C, LT11 notice, LT38 notice, LT39 notice, Letter 2531, Letter 4310C. For the codes on an IRS account transcript, see the IRS transcript codes lookup. For how interest and penalties are worked out on a balance, see the IRS penalty and interest calculator.
Sources
- Understanding your letter 4800C: what the letter or notice is, what to do, and the help and reference items. Read November 2, 2026.
IRS page last reviewed January 30, 2026. This page restates what the IRS page says and adds nothing beyond it: no timelines, outcomes or advice that the IRS page does not state. The IRS can change a letter page at any time; the letter you received controls, including its response date and contact details.
Frequently asked questions
What is IRS Letter 4800C?
The IRS page says: “We’re proposing a change to your tax return.”
How long do I have to respond to Letter 4800C?
The IRS page says to complete and return the Response Form within 30 days from the date of the letter.
How can I reply to a Letter 4800C?
The IRS page lists the Documentation Upload Tool as the fastest way, a fax to the number in the letter, or mail using the enclosed envelope.
What happens if I don’t respond to Letter 4800C?
The IRS page says it will send a notice requesting additional documents or an explanation of adjustments it made to your tax, withholding and credits.
How long does the IRS take after I respond to Letter 4800C?
The IRS page says it will contact you within 180 days if it has questions, and that it takes about 9 weeks to review your response and make any changes.
Not tax or legal advice
This page summarizes IRS letter and notice pages and is not tax, legal or financial advice. It does not tell you how to respond beyond what the IRS page states. The letter you received controls. A CPA, enrolled agent or tax attorney, or the IRS number printed on your letter, can confirm what applies to you. Everything runs in your browser; nothing you enter is sent anywhere.