When Steven Cohen’s eldest daughter Lily lost her first tooth, he — or, rather, the Tooth Fairy — left $20 under her pillow. Not because the Upper West Side dad has money to burn, but because in today’s increasingly cash-free society, finding small bills lying around the house was like, well, pulling teeth.

“I didn’t have anything else. I panicked,” Cohen, 55, who works in real estate, told The Post.

Now, his 5-year-old daughter, Scarlett, who is saving up for a Buzz Lightyear doll and a trampoline, is champing at the bit for her first loose tooth — and she’s already got visions of Andrew Jacksons dancing in her head.

“The bar is higher now. I didn’t really think that far in advance,” Cohen confessed.

While the well-intentioned dad may not have set out to give his daughters the impression that the Tooth Fairy is made of money, $20 for a first tooth has actually become the norm in plenty of households across the country as the treasured childhood tradition is impacted by sky high inflation. The latest data from insurer Delta Dental found the average cash gift is $5.36 per tooth – a record high in the 24-year history of the poll.

For Josh Willink, 36, leaving $20 for his daughter Remy, 8, after she lost her first tooth just made sense, given the rising cost of just about everything these days.

“Growing up you’d get a $1 from the Tooth Fairy. You could go to the store and buy anything you wanted. Now, $1 doesn’t even buy you anything,” Willink, who lives in Holland, Mich., and runs the parenting and travel site ThirdCoastTribe.com, told The Post.

When his middle daughter Jade, 5, loses her first tooth, he’ll likely shell out a $20 and set the minimum at $5 after that — enough, he says, to buy herself something nice at the nearby Five Below store.

Less organized parents are flocking to social media and chat forums to find out the appropriate going rate for a first tooth nowadays — and some of them are shocked by what they find.

“I had to look up and see how much the Tooth Fairy pays out for the first tooth. We decided to go with $20 because she’s been so excited,” one parent wrote in a Reddit thread that sparked outrage among other parents, who grew up getting a quarter or less under their pillows. Even her parents found the amount of money absurd.

“Sorry mom and dad, the tooth fairy suffers from inflation as well,” the unapologetic user wrote, noting that in their house, the rates are now $10 to $20 for the first tooth, and $1 to $5 for each lost tooth thereafter — a whopping $100 per child.

Lesley Koeppel, a psychotherapist in a private practice in New York City, warns that rewarding kids with large sums of cash when they didn’t really earn it comes with a downside.

“Yes, it’s an exciting milestone that you want to celebrate, but you don’t want to give them a false sense of accomplishment. You don’t want to give this impression that you just get money for no real reason,” Koeppel told The Post. 

There’s nothing wrong, however, Koeppel said, with creating an educational opportunity for the child.

“It can be an opportunity to teach them about the one-third rule – keeping a third, saving a third and donating a third to charity,” she said.

And while some parents might balk at the increased rates, for Cohen, once reality set in, he realized he’d made the right decision to dole out that first $20 bill. It wasn’t enough to cover the tab at Starbucks, he said, when little Lily generously offered up her earnings to treat her parents to coffee and snacks. 

“We had to chip in,” he said.