What this notice is about We issue a CP12 Notice when we correct one or more mistakes on your tax return, and a payment becomes an overpayment, or an original overpayment amount has changed. What you need to do Review the notice and compare our changes to the information on your tax return. If you agree with the changes we made, no response is required. You should receive a refund check in 4-6 weeks, as long as you don't owe other tax or debts we're required to collect. You may want to correct the copy of your tax return that you kept for your records, but do not send it to us. If you don’t agree, contact us within 60 days of the date of your notice. By telephone: Call us at the telephone number shown on your notice. The fastest way to resolve many return errors is by telephone. Some cases require additional information that you may provide verbally. If a missing or corrected form or document is needed, you may fax it to us while on the telephone. Either way, we may be able to correct your account immediately. By mail: Please include a copy of the notice along with your correspondence or documentation and allow 30-60 or more days for a resolution. Frequently asked questions Why did I receive this notice? We issue Notice CP12 when we correct one or more mistakes on your tax return, and: The overpayment is different from the one you expected, or You have an overpayment when you thought you owed money or had an even balance. How can I find out what caused my tax return to change? Please contact us at the toll-free number listed on the top right corner of your notice for specific information about your tax return. What should I do if I disagree with the changes you made? If you disagree, contact us at the toll-free number listed on the top right corner of your notice or respond by mail to the address on your notice. If you write to us, include a copy of the notice along with your correspondence or documentation. If you contact us within 60 days of the date of this notice, we'll only reverse math error adjustments we made to your account. However, if you can’t provide us additional information that justifies the reversal and we believe the reversal is in error, we'll forward your case for audit. This step gives you formal appeal rights, including the right to appeal our decision in court. After we forward your case, the audit staff will contact you within five to six weeks to explain the audit process and your rights. If you don't contact us within the 60-day period, you'll lose your right to appeal our decision before payment of tax. After 60 days, reversal requests must be substantiated. Helpful information Notice 746, Information About Your Notice, Penalty and Interest PDF Publication 5, Your Appeal Rights and How to Prepare a Protest PDF Avoiding Future CP12 notices Consider filing your taxes electronically. Filing online can help you avoid mistakes and find additional credits and deductions you may qualify for. In many cases, you can file free. Learn more about e-file. Reference Tools Publication 1, Your Rights as a Taxpayer Publication 17, Your Federal Income Tax Full list of tax forms and instructions Need Help? You can authorize someone to contact the IRS on your behalf. See if you qualify for help from a Low Income Taxpayer Clinic. If you can’t find what you need online, call the IRS number at the top of your notice or letter.