Customers are increasingly fee-d up, and it’s just getting worse.

You better check your restaurant bill more closely — otherwise, you might be unknowingly paying for a “wellness fee” or a “kitchen appreciation fee” in addition to a tip.

Restaurants across the U.S. are implementing bizarre add-ons, which can shockingly tack an extra 20% onto a check.

And that’s before any gratuity.

They are so rampant in Los Angeles that people are even making spreadsheets to warn diners.

NYC tech worker Anna Nikkinen was blindsided to see a 5% wellness charge — coming in at just over $15 — plopped onto her already pricey meal at LA’s trendy Mother Wolf.

The surcharge is “added to all checks in support of health benefits for our staff, but it is not a fee for service,” according to the restaurant’s menu.

“That’s some ridiculous fee … I’m not really sure why customers are paying for that,” Upper West Sider Nikkinen told The Post of her recent sticker shock — which was the same cost as her torta di oliva dessert, a ritzy olive oil plum cake.

It seems this new super weapon is blasting wallets nationwide in a post-COVID world where patrons are being taxed and charged with so many add-ons that President Joe Biden has even stepped in to declare war on so-called “junk fees.”

“It’s just kind of crazy because it’s not like the food and drinks are cheaper — and we’re still paying for employees’ benefits,” Nikkinen ranted.

Not until the next day did someone point out to Nikkinen that such add-ons are optional — though you must ask them to be removed, which is noted on Mother Wolf’s menu and receipts, according to a representative for Chef Evan Funke.

“You have to be a private investigator these days just to order food,” an irked Nikkinen continued, adding that there’s also social pressure to not call attention to a higher-than-expected bill in a public, high-end setting like Mother Wolf.

In the Big Apple, specific code regulations do not allow for “wellness” or “kitchen appreciation” charges, at least for now.

However, CNBC writer Monica Pitrelli recently complained that an NYC hotel had charged her numerous “destination fees,” including three ringing in at $35 each.

And when she tweeted about those “junk fees,” an anonymous poster replied that they had been hit by a “kitchen staff appreciation fee” at an unnamed NYC restaurant, which they deemed “ridiculous.”

Elsewhere in the tri-state area and beyond, fees are piling up.

Tabla, an Italian restaurant in the Catskills village of Tannersville, supplements each bill with a substantial “10% living wage charge.”

“This fee creates a more sustainable and equitable guaranteed pay rate for all employees,” according to a footnote on the menu.

‘You have to be a private investigator these days just to order food.’

Owner David Schneider did not immediately respond to a request for comment from The Post.

In New Jersey vacation spot Asbury Park, popular pizza purveyor Talula’s tacked on its own 3.5% “kitchen appreciation fee” last year to combat higher costs for ingredients like tomatoes, cheese, oil and meats, according to NJ.com.

The move reportedly drew some praise but also significant rage — and the eatery eventually wound up ditching the charge.

And farther north in Cambridge, Massachusetts, a restaurant called Vincent’s upped the ante on their “fair wage surcharge” to a staggering 20% as well.

Separate ownership of two other Massachusetts restaurants adopted that same model in 2015 — well before COVID — which inadvertently foreshadowed the future trend.

“We think that within five years the majority of restaurants will have adopted some measure to address this critical issue,” the bosses of Tres Gatos and Casa Verde in Jamaica Plain predicted in an open letter at the time.

They clearly weren’t far off.

Romain Turpault, who owns high-end Connecticut eateries including Union League Cafe near Yale University in New Haven, instituted a more modest 4% customer charge for a “kitchen appreciation program” during early COVID.

“Every couple of months, we will have a guest that wants to speak to a manager to understand why we do that instead of increasing our prices,” he told The Post of his 30-year-old establishment.

“To me, at the end of the day, it’s actually exactly the same thing. Only we show why the price has actually increased.”

Turpault, like many restaurateurs, already had to adjust the prices of dishes — especially those with chicken and beef — to combat egregious inflation since the pandemic. He added that qualified and experienced kitchen staff has also been tough to come by since 2020.

But throwing a kitchen fee on top of that already boosted total would come off tasteless, the chef added.

Still, he said the 4% protocol is being “fairly well-received,” thanks to such transparency.

“We make it very clear on our menu — it’s actually at the top,” he told The Post, adding that he believes customer awareness “is important.”