I will be mailing in my return today. My question is: Do I need to file for an extension since it wont get there for a few days? I don't owe anything

[MinhT1]

If your tax return is post-marked today April 15, you won't need to file an extension.

[Calisurvivor]

It is recommended that you stand in line at the post office and hand it to them to weigh and pay the postage with them, as it will then be stamped right on the envelope, or pay the post office a small amount so you have proof of mailing.  Just be sure to include enough postage on the envelope!  It is "mailed" or "transmitted" by April 15th, not "received" by that date.

[TomK2023]

If you don't owe any balance due, then as long as your return is post-marked by 11:59pm tonight, you should be fine.