Tax Extension Toolkit
Complete guide to filing for an extension — Form 4868 for individuals, Form 7004 for businesses. Includes a payment calculator and a confirmation checklist so you don't get hit with the failure-to-pay penalty.
Which form do you need?
Other forms exist for specific situations: Form 8868 for tax-exempt organizations (Form 990 series), Form 2350 for citizens/residents abroad who need extra time to qualify for the Foreign Earned Income Exclusion (FEIE).
Payment estimator (Form 4868)
Estimate what you'll owe so you can pay it with the extension. Rough math is better than no math — the IRS just needs a good-faith estimate.
Quick Estimate
Pay this amount with your extension via IRS Direct Pay, EFTPS, debit/credit card, or check with Form 4868. Paying at least 90% of total tax owed with the extension avoids the failure-to-pay penalty (interest still accrues on any unpaid balance).
How to file Form 4868 (3 methods)
- E-file with payment — fastest. Use tax software (TurboTax, H&R Block, FreeTaxUSA) or IRS Free File. Select "request extension" and pay electronically. Confirmation arrives within 24-48 hours.
- IRS Direct Pay — go to irs.gov/payments/direct-pay, select "Extension" as the reason. Paying through Direct Pay automatically files the extension — no separate Form 4868 needed.
- Paper file — mail Form 4868 with payment by check to the IRS address for your state. Must be postmarked by April 15. Use certified mail for proof.
How to file Form 7004 (business)
- E-file via tax software — required for many business filers and recommended for everyone. Most professional software (CCH Axcess, Drake, ProSystem fx) supports F7004 e-file.
- EFTPS — for paying the estimated tax due with the extension. Free, secure, must be enrolled in advance (allow 5-7 business days for first-time enrollment).
- Mail — paper Form 7004 to the IRS address for your entity type and location. Address varies; check current Form 7004 instructions.
For S-Corps and partnerships, the original deadline is March 15; the extended deadline is September 15. For C-Corps, March 15 doesn't apply — the original is April 15, extended to October 15.
State extensions
Most states accept the federal extension and don't require a separate state filing. But some require their own form, and some require it even if you don't owe state tax. Common state-specific forms include CA Form 3519, NY Form IT-370, MA Form M-4868.
If your state doesn't piggy-back on the federal extension, the state extension is usually required by the same April 15 deadline. Check your state Department of Revenue website before filing.
Common extension mistakes
- Treating extension as payment deferral — the #1 mistake. The extension only extends filing, not paying. Pay your estimated balance with the extension to avoid the failure-to-pay penalty (0.5% per month).
- Missing the original deadline anyway — Form 4868 must be filed by April 15, not after. Late-filed extensions are invalid; you're treated as having no extension.
- Underestimating tax owed — if your estimate is significantly off and you owe substantially more on the actual return, the failure-to-pay penalty applies to the shortfall.
- Forgetting state-specific extensions — if your state doesn't auto-accept federal, you can owe state late penalties.
- Not keeping confirmation — keep the e-file acknowledgment, Direct Pay confirmation, or certified mail receipt. You may need to prove timely filing.
- S-Corp/partnership owners missing the March 15 deadline — flow-through K-1s won't be ready for owner-level returns until the entity files. Both the entity and the owner often need extensions.