The IRS expects to receive about 135 million returns by the end of the day. But for those who can't make it, experts recommend filing a 6-month extension to avoid penalties.
"The late filing penalty is up to 25 percent of the total amount due, which is just incredible," said Eileen Brown, district manager at H&R Block.
Those who need to file an extension can do so online at IRS.gov, which will extend the deadline to Oct. 15. To get the extension, applicants must estimate their tax liability and should pay at least 90 percent of the amount due, Brown said.
Taxpayers can also avoid interest and late-payment penalties by filing a return and setting up a payment plan, experts said.
"The ones who file early right after Jan. 22, they get money back. People like me who owe, we postpone as long as possible," said Fritz Lukken, of Long Beach.
Some Southern California post offices are staying open until midnight, including:
- Los Angeles - 7001 S. Central Ave., Los Angeles, CA 90001
- Santa Ana - 3101 W. Sunflower Ave. Santa Ana, CA 92799
- Santa Clarita - 28201 Franklin Parkway, Santa Clarita, CA 91383
- San Bernardino - 1900 W. Redlands Blvd., San Bernardino CA 92403