Notice Type
Letter 4800C proposes an adjustment to a refundable credit or withholding amount claimed on your return, typically after the IRS's review identifies something that doesn't match its records or that needs more support. It explains the proposed change and gives you a chance to respond with documentation before it becomes final, and this type of notice often fits well within our standard $45 notice review, since it usually just requires understanding the proposed change and confirming whether it's accurate.
Before You Respond
Letter 4800C is a proposal, not a final bill, but it becomes final if it goes unanswered, so it's worth attention rather than being set aside. Check the response date printed on your actual letter — Letter 4800C states a specific date by which you need to agree, disagree, or provide documentation, and that date is what determines your timeline, not a general rule of thumb. If no response is made by that date, the IRS generally proceeds with the proposed adjustment, which can reduce or eliminate a refund or create a balance due. Responding by the date on your letter, even just to provide supporting documentation, keeps your options open.
Know Before You Act
Before agreeing to the proposed adjustment or assuming it's final, it helps to understand two things: which credit or withholding amount the IRS is questioning, and whether you have documentation that supports what was claimed. The IRS may be correct that something doesn't match. But there can also be documentation that simply wasn't submitted yet, a credit that qualifies but needs more support to prove, or a reporting difference between what you claimed and what a third party reported. Knowing which of these applies to your situation is what determines whether the proposed change is something to accept or something worth supporting with documentation.
Start with a secure notice upload and a free IRS notice summary. If you want organized next steps, optional $45 Review & Guidance is a one-time purchase with no subscription. It may include an Action Plan, records to gather, response options, and case questions. When the information and supporting documents provided support a written IRS response, you can use the action steps provided to prepare it yourself or unlock the option for Think Twice Tax to draft a personalized response letter for you.