A missing half-inch really adds up.

A card-carrying Subway devotee is fighting back against sub-par sandwiches, filing a lawsuit alleging the fast-food giant ripped off customers for more than $142 million with its short “Footlongs.”

Jason Leslie, 32, of Marlboro, NJ, says he was spurred on to sue the sandwich maker yesterday after he saw an article in The Post last week that revealed the “$5 Footlong” subs often don’t measure up.

Leslie, who carries a Subway Rewards card and estimates having eaten about 50 of the sandwiches a year since he was 18, bought a Footlong meatball sub four days later for $8 that ended up being short of 12 inches. “They advertise in all these commercials, ‘Footlong, Footlong, Footlong,’ and now I feel like an idiot,” the used-car dealer told The Post. “I can’t believe I fell for that trick.
INCHING FOR A FIGHT: Jason Leslie of Marlboro, NJ, estimates he has eaten 50 Subway Footlong sandwiches each year for the past 14 years.

“The sandwiches are anywhere between a half-inch to an inch shorter . . . I feel cheated.”

“A foot is 12 inches. They call it the Footlong, making people believe they’re getting a foot-long sandwich,” said attorney Stephen DeNittis. “If they were calling it the ‘Big Sandwich,’ or the ‘Big Kahuna,’ this case wouldn’t have been filed.” DeNittis, who represents Charles Pendrak and John Farley, said he planned to file a similar state suit in Philadelphia today.

The lawyer hired an investigator to measure sandwiches at 17 Subways near his office, and found that all sold Footlong subs that were less than 12 inches, he said.

Preempting the inevitable "I used my 'anatomy' to confirm this shortcoming" from the usual Bahamian, WV and SCarol suspects.