'Girl Math' Is Going Viral On TikTok — But It Has A Cost

Who hasn't used this kind of logic when justifying purchases at least once in their life?
"Girl math" is a humorous trend on TikTok that people are using to justify their purchases.
Maddie Abuyuan/HuffPost
"Girl math" is a humorous trend on TikTok that people are using to justify their purchases.

If you have been on TikTok lately, you have likely encountered the TikTok trend where women explain and justify spending habits as “girl math.“

It appears to have originated from clips by a New Zealand radio show called “Fletch, Vaughan & Hayley” on the topic. The girl math segments go like this: a caller will share the price of a big purchase like spending about $999 on a luxury tote, or $5,600 on four nights of Taylor Swift tickets, or a $699 Dyson hair dryer. And then the hosts help the caller justify the exorbitant price by estimating the number of times it is expected to be used or what the caller may be saving in return, so that the total is “basically free.” Girl math.


Big fans of girl math 🫶💁♀️ #girlmath

♬ original sound - FVHZM

The radio show’s term has prompted people on TikTok to share their own examples of the sometimes-contradictory logic within girl math that makes not only big purchases but small ones feel good, too.

One popular TikTok by user @samjamessssss shared examples including “Anything under $5 feels like it’s pretty much free ... even like tickets that I buy months in advance, I show up to the concert and I’m like, ‘This was like a free concert.’”

It can also make doing returns feel like you’re making money, or using money in your Venmo account to pay someone back feel free, as TikToker @mckennaelianna put it.


somehow it makes sense #girlmath 🤷🏼♀️

♬ original sound - kenna 📚🍷

Of course, girl math is meant to be a tongue-in-cheek joke. It’s “fun logic,” as one TikToker puts it. When creators spell out their convoluted calculations, it hints at how the creators behind these girl math videos are on some level aware that though it may feel “basically free” or “pretty much free,” it’s not.

But the many millions of views these videos have gotten suggest that the practice of girl math has resonated with a lot of viewers. When I asked Jen Hemphill, an accredited financial counselor and host of podcast “Her Dinero Matters,” about why that might be, she said people appreciate hearing about other people’s imperfections.

“People connect, because one: we’re in some trying times,” she said, “It’s relatable to them, because chances are they’ve made a mistake. And so being able to connect with that and say, ‘Hey, I’ve been there too’...feels good.”

One word of caution: If you do start to believe it’s more than a joke and are using it to justify overspending beyond your means, that is the tipping point of when girl math is no longer fun.

To figure out this tipping point, Hemphill said to ask yourself: “Why are you doing girl math? Is it just to justify and you’re feeling some guilt and you’re needing to feel good without a plan, or are you giving yourself some grace and you know you’re getting yourself back on track?”

Take the “cost per use” calculations many people doing girl math do, as one example. Hemphill said weighing this can be a good way to make purchasing decisions. “But it needs to be done prior to the purchase,” she said.

“Why are you doing girl math? Is it just to justify and you’re feeling some guilt...or are you giving yourself some grace?”

- Jen Hemphill, accredited financial counselor

Some examples of girl math may not be as savvy. “Cash is not real money, so if I buy something with cash, it is free,” one explainer video states. According to a 2023 paper in the Journal of the Association for Consumer Research that looked at over 118,000 real-world purchases, consumers prefer to pay in cash when they want to forget what they bought because “cards create a paper/electronic trail that aids memory retrieval.”

But it’s not just girls who find cash purchases easier to justify ― it’s everyone.
So why call these financial justifications girl math when it’s a behavior that is not exclusive to girls?

Beyond the appeal of gendered essentialism, one reason might be because “girl math” follows the savvy marketing trend of people online attaching “girl” to everyday activities, so that they are considered more engaging and fun. (See: “girl dinner,” “hot girl walks,” and the many books about adult women that have “girl” in their title.) For better or worse, “woman math,” “hot woman walks” and “woman dinner” do not have the same mass appeal for consumers of these trends.

Experts warn against making ‘girl math’ a regular habit.

For some, following girl math is not a laughing matter because it can come with real negative consequences to society and to your bank account.

Vivian Tu, a former J.P. Morgan equities trader and upcoming author of “RICH AF: The Winning Money Mindset That Will Change Your Life,” said she knows it’s a joke, but she believes “it has the same energy as ‘women are bad drivers,’” because it can perpetuate “the stereotype that women are bad with money or math, or don’t take their finances seriously is detrimental to society.”

Tu cautions against thinking that little purchases are not adding up. “I am a huge proponent of not cutting out your everyday pleasures. But you need to acknowledge that those things bring you joy and cost money,” she said.

Tu gave the example of daily $5 purchases. “A $5 purchase every day that ‘doesn’t count’ leads to an extra $1,825 in expenses annually,” she said. “It’s totally OK to want to spend money and enjoy spending money, but doing it with intention means you not only get to enjoy your purchase, but you also won’t end up with a deficit in your budget.”

Hemphill, meanwhile, said she does not think the girl math trend can either be only good or bad. “Some might live by ‘girl math,’ and that’s the danger, right? But others will know...‘I’m giving myself some grace instead of beating myself up for making this financial decision. And that’s OK.’”

Whether or not you do girl math, have a plan for how you’re spending before you do it. Because we all have different values of what’s important to us, Hemphill advises making your big and small purchases with intention.

“As a financial counselor, I’m not going to tell you, ‘I cannot believe you put Beyoncé and Taylor Swift tickets on your card.’ It’s a personal choice, but I can guide them,” she said. “‘How can you enjoy that, and make a plan to make sure you pay that credit card off, so you don’t carry a balance?’ Because then that Beyoncé concert, Taylor Swift concert is going to be incurring interest, and after that, is that really going to be worth it?”

Because personal finance can be so personal, “It’s about really being proactive in that decision and knowing what is the result of that decision, and if you’re OK with that,” Hemphill said.