Form 3520 Due Date in 2026: When You Actually Need to File
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The dates
Form 3520 is due on the same day as your individual income tax return (Form 1040).
| Tax year | Standard deadline | Extended deadline |
|---|---|---|
| 2024 | April 15, 2025 | October 15, 2025 |
| 2025 | April 15, 2026 | October 15, 2026 |
| 2026 | April 15, 2027 | October 15, 2027 |
If the 15th falls on a weekend or DC holiday, the deadline shifts to the next business day. The 2026 filing for tax year 2025 falls on a Wednesday — no shift.
Getting an extension
You do not file an extension specifically for Form 3520. You extend your individual return using Form 4868 (filed by April 15), and your Form 3520 deadline shifts to October 15 automatically. The same Form 4868 covers both.
Important: Form 4868 extends the time to file, not the time to pay. Form 3520 itself does not generate a tax liability for most filers (reporting a foreign gift is informational, not taxable), so there is usually nothing to pay. But if you also owe income tax on your 1040, that income tax is still due April 15 even with an extension to file.
What if you are a US person living abroad
US citizens and green-card holders abroad get an automatic two-month extension to June 15 without filing anything, under Treas. Reg. 1.6081-5. You can still file Form 4868 for an additional four months to October 15.
To use the automatic two-month extension you write "Taxpayer Abroad" at the top of your forms and attach a statement explaining you were outside the US on April 15. Tax preparation software usually handles this for you. Our app does not yet — for V1 you would file by April 15 to be safe.
What happens if you miss the deadline
The penalty for late Form 3520 (or unfiled Form 3520) under IRC § 6039F is the greater of:
- $10,000, or
- 5% of the gross reportable amount, per month late, up to 25% of the total
On a $200,000 foreign gift, that maxes out at $50,000. The penalty accrues monthly until you file, then stops.
The IRS has discretion to abate the penalty for reasonable cause — if you can show you did not file because of circumstances beyond your control (reliance on bad advice from a tax professional, hospitalization, natural disaster) and you filed as soon as you reasonably could. Reasonable cause requests are not automatic; you usually need to attach a written statement.
What does NOT extend the deadline
- Receiving the gift late in the year does not delay the deadline beyond April 15 of the following year.
- Not knowing about Form 3520 is not an extension.
- A pending IRS examination of another year is not an extension.
- Mailing on April 15 but getting it postmarked April 16 is late. Mail by April 14 to be safe, or use certified mail with a postmark scan.
Filing on the deadline itself
Form 3520 is paper-only and mails to the IRS Ogden Service Center in Utah. The "timely mailed = timely filed" rule (IRC § 7502) applies — your USPS postmark on April 15 makes the filing timely even if the IRS receives it later. To prove this, mail certified with return receipt; keep the green card.
If you wait until April 15 to mail, go to the post office in person and ask the clerk to hand-cancel the certified-mail receipt while you watch. Online or drop-box postmarks can be dated the next business day depending on the time you mailed.
3520file is software, not a CPA firm or law firm. We prepare IRS Form 3520 based on the facts you provide. For advice on your specific situation, talk to a tax attorney or CPA. The above is plain-English explanation, not tax advice.