Most of us consider April 15 as D-day, or in this case, T-day (Tax Day). However, while that’s usually the case, the 15th is not engraved in stone.

When April 15 (or any other tax deadline) falls on a Saturday, Sunday or legal holiday, you get until the next business day to file your return. In most cases, that means it simply has to be postmarked that day, not physically in the Internal Revenue Service’s hands (or bank account).

U.S. taxpayers who live outside the country are given a bit more time to file: until June 15, with the same Saturday, Sunday, holiday considerations.

And some business owners operate on a fiscal year — a year ending on the last day of any month other than December — rather than the calendar year. If you use a fiscal year, your return is due by the 15th day of the fourth month after the close of your business year.

Filing on time

Regardless of the actual tax due date, avoid filing your tax return late. Late filing only makes your life more complicated and it could cost you added penalties and interest fees.

Your return is considered filed on time if the envelope is properly addressed and postmarked by the due date. Many post offices stay open late when tax day rolls around, so check with your local postmaster.

More and more filers are opting to file electronically and some put off hitting the “send” button until 11:55 p.m. on tax day. That’s OK, too, but be aware that a high volume of users could slow down your transmission or your system could crash, meaning that your e-filed return could end up getting to the IRS late.

The filing deadline and guidelines also apply to extension requests. With extensions, you can ask the IRS for more time if you find you can’t get all the forms completed by mid-April. The table below shows the normal tax deadlines and the added time filing extensions can provide:

Tax deadlines
For most taxpayers For certain taxpayers

outside the

United States

No extension requested April 15 June 15
Extension request (file Form 4868) Oct. 15 Oct. 15

Before you jump for joy, we must point out that an extension of time to file is NOT an extension of time to pay any tax you may owe. You need to make an accurate estimate of your tax bill and send that payment with Form 4868. If you can’t pay the full amount with Form 4868, you still can get the extension, but you’ll owe interest on the unpaid amount.

One extension form, six more months

Form 4868 may be your best tax friend if you can’t file your return on time. Thanks to a regulation change, it now will get you six extra months — until Oct. 15 — to get your paperwork in order.

If you’re filing a fiscal-year return, which is the case for most individual taxpayers, the extra time is automatic. You don’t need to explain why you need it as long as you ask for it by submitting Form 4868 by the regular April due date for your return.

Once you do this, you can file your Form 1040EZ, 1040A or Form 1040 anytime before the six-month extension period ends.

Just remember, Oct. 15 is it. No taxpayer gets more than six months of extra time to file a return.