Understanding your CP51C Notice

What your notice is about

We computed the tax on your Form 1040, 1040A or 1040EZ. You owe taxes.


What you need to do

  • Read your notice carefully. It will explain how we calculated your tax return.
  • You don't need to do anything if you agree with our calculations.
  • Contact us if you disagree with the amount of tax we computed.

Answers to common questions

What should I do if I disagree with the notice?
Call us at the toll-free number on the top right corner of your notice. Please have your paperwork (such as cancelled checks, amended return, etc.) ready when you call.


Tips for next year

Consider filing your taxes electronically. Filing online can help you avoid mistakes and find credits and deductions that you may qualify for. In many cases you can file for free. Learn more about e-file.

Printable samples of this notice (PDF)

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, you can call the IRS at the 800, 866, or 888 number listed on the notice.