NEW YORK (MainStreet) — October 15 is the statutory deadline for submitting your extended federal and state income tax returns.

This doesn’t mean that the IRS or state agency must receive your return in its hands by October 15. If you are mailing a paper return, it simply must be postmarked October 15.

So if you have not already done so, electronically send your computer-generated 2013 returns, or put your paper returns in the mail, today! Do it even if you cannot pay all or any of a balance due on the return.

Don’t delay. While there may be a local Post Office somewhere that will be open until midnight on October 15, as some are on April 15, most will close their doors by 5:00 p.m.

And while it is not a requirement, it couldn’t hurt to mail your returns “certified” or “return receipt” as additional documentation of the postmark.

Why is this so important?

If your return is not submitted or mailed today it will be considered to be “filed late.” The penalty for “late filing” of a federal return with a balance due is 5% of the amount due per month, or part thereof. The penalty for “late payment” of a balance due on a timely filed extended federal return with a balance due is 0.5% (.005) of the amount due per month, or part thereof.

If you owe your Uncle Sam $1,000 and you submit or mail your extended 2013 Form 1040 by October 15, with payment in full, the penalty will be $30.00. If you submit or mail your extended return without a payment by October 15, and send the $1,000 balance due on November 8, the penalty will be $35.00. If you submit or mail the return on November 2, with payment in full, the penalty will be $350.00.

If your return shows a refund due to you then there is no problem if you mail your return next week, next month, or next year. You will only be penalized if you owe money to the government.

And if you did not submit or mail a Form 4848 and any required state extension request form by April 15, you are out of luck. Regardless of when you submit your finished return you will be subject to the “late filing” penalty if you owe money.

--Written by Robert D. Flach for MainStreet