Fill out Form 8878 (IRS e-file Signature Authorization for Form 4868 or Form 2350) online
Form 8878 is the IRS e-file Signature Authorization specifically for electronic filing of Form 4868 (Application for Automatic Extension of Time to File) or Form 2350 (Application for Extension of Time to File U.S. Income Tax Return for Citizens and Residents Abroad). It authorizes an Electronic Return Originator (ERO) to submit the extension request on the taxpayer behalf.
How to fill out Form 8878 (IRS e-file Signature Authorization for Form 4868 or Form 2350)
Determine the extension type
Decide whether you are filing Form 4868 (standard automatic 6-month extension for U.S. taxpayers) or Form 2350 (extension for U.S. citizens and residents living abroad who expect to qualify for the foreign earned income exclusion).
Review the extension details
Before signing Form 8878, review the extension form prepared by your ERO. Verify your estimated total tax liability, total payments already made, and the balance due amount you intend to pay with the extension.
Enter your PIN and sign the authorization
Select a five-digit self-select PIN (any five numbers except all zeros) to serve as your electronic signature. Enter it on the form, then sign and date. If filing jointly, both spouses must provide PINs and sign.
Provide to your ERO for transmission
Give the signed Form 8878 to your ERO (tax preparer). The ERO enters your PIN, signs, and transmits the extension request electronically. The ERO retains the signed form; you should keep a copy for your records.
About Form 8878 (IRS e-file Signature Authorization for Form 4868 or Form 2350)
Who needs this form
Taxpayers who use a paid preparer or tax software provider to electronically file an extension of time to file their federal income tax return (Form 4868) or an extension for U.S. citizens abroad (Form 2350). Both the taxpayer and the ERO must sign this form before the extension is transmitted.
Where to submit
Do not file Form 8878 with the IRS. The ERO retains the signed original (or electronic copy) for three years from the return due date or the date the extension was filed, whichever is later. The taxpayer should keep a copy for their records.
Source and content freshness
- Reviewed: 2026-02-24
- Filing deadlines may shift for weekends and holidays. Verify due dates with official instructions.
Common mistakes to avoid
- Confusing Form 8878 (for extensions) with Form 8879 (for the actual tax return e-file authorization)
- Not verifying the estimated tax payment amount on the form before signing
- ERO transmitting the extension before obtaining the signed Form 8878 from the taxpayer
- Failing to retain the signed form for the required three-year retention period
Frequently asked questions
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What is the difference between Form 8878 and Form 8879?
Form 8878 is used to authorize the electronic filing of a tax extension (Form 4868 or Form 2350), while Form 8879 is used to authorize the electronic filing of the actual tax return (Form 1040). If you are e-filing both an extension and a return through a preparer, you would sign Form 8878 for the extension and Form 8879 for the return.
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