Should You FedEx Your Ballot? No.

With Election Day a week away, those who have waited until nearly the last minute to vote by mail may be considering turning to an express carrier, thinking that may expedite the process.

But experts say voters should use either a secure ballot drop box or the United States Postal Service instead to avoid the risk of running afoul of rules for voting by mail, which vary by state.

“If you have a mail ballot but you haven’t mailed it back yet, vote it today and return it in person if you can,” said David Becker, the founder and executive director of the Center for Election Innovation & Research, a nonprofit, nonpartisan group that seeks to increase voter participation and improve the efficiency of elections.

“Get your ballot back as soon as possible in a drop box, or an election office if at all possible,” he added. “Or alternatively, take it with you to an early voting location and drop it off there, or surrender it and cast an in-person ballot.”

The question of whether it is OK to submit a ballot by private carrier rather than by regular mail resurfaced over the weekend when the singer Lady Gaga posted a photo of herself on Twitter holding her ballot and a FedEx envelope.

“Ballot’s here!” she said.

Experts urged caution. Some states don’t accept ballots if they are delivered by a private carrier. And states generally require ballot envelopes to carry a postmark, which only the Postal Service can apply.

Using a carrier like UPS or FedEx can also cost more. The Postal Service treats ballots as first-class mail, meaning they can be returned with a 55-cent Forever stamp. In many cases, voters are able to return completed ballots in a prepaid envelope at no cost.

“Voting is one of our most important civic duties as citizens,” Matthew O’Connor, a spokesman for UPS, said in a statement on Monday. “Each state is responsible for their own rules regarding mail-in ballots and the requirements for validity vary greatly from state to state.”

He added that “while there is no single set of rules for this, UPS always follows all applicable laws and regulations.” He suggested that people check with “state authorities who set the rules to see if they will accept a ballot if delivered by a private express carrier.”

FedEx does accept individual ballots for shipment. On Saturday, the singer Lady Gaga posted a photo of herself on Twitter holding her ballot and a FedEx envelope.

“Ballot’s here!” she said.

Jennifer Caccavo Cordeau, a spokeswoman for FedEx, said in a statement that “U.S. election absentee and mail-in ballots are predominantly handled by the U.S. Postal Service.”

She also suggested that “customers planning to return their ballots via FedEx should closely review their state’s guidelines on absentee voting and deadlines for ballots or related election documents.”