 scale(0.75)'%3E%3Crect x='6' y='14' width='52' height='36' rx='4' fill='%23e9dcbc' stroke='%2322262b' stroke-width='3'/%3E%3Cpath d='M8 17l24 18 24-18' fill='none' stroke='%2322262b' stroke-width='3' stroke-linejoin='round'/%3E%3Ccircle cx='46' cy='40' r='9' fill='none' stroke='%239c2f22' stroke-width='2.5'/%3E%3Cpath d='M40 40h12' stroke='%239c2f22' stroke-width='2'/%3E%3C/g%3E%3Ctext x='58' y='33' font-family='Rockwell, Georgia, serif' font-weight='700' font-size='24' fill='%2322262b'%3EIRS Letters and Forms%3C/text%3E%3C/svg%3E)
Notice code 421
Notice code 421 (Default) — You failed to compute the additional tax owed as a result of the sale of real property. We have adju…
You failed to compute the additional tax owed as a result of the sale of real property. We have adjusted your return accordingly.
What to do next
Start with these steps before you reply.
421
Read the notice carefully and note any deadline. Gather returns, notices, and payment records. Book a free strategy session before responding if the amount is large, unclear, or collection language appears.
What the IRS language says
You failed to compute the additional tax owed as a result of the sale of real property. We have adjusted your return accordingly.
What it usually means
421 is in our IR Manual catalog. Official wording is dense — we translate it for business owners and individuals and map realistic next steps.
Related
Find another letter
Every notice in this library, sorted the way the IRS numbers them.