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- Move over "girl dinner" and "lazy girl jobs," a new personal finance trend has gone viral on TikTok.
- Called "girl math," this humorous trend has users breaking down purchases into their smallest possible units to justify them.
- One critic says the trend justifies overspending.
A new personal finance trend has TikTok users recommending humorous new ways to rethink their spending habits — like imagining that anything under $5 is free, or measuring the cost of big-ticket items by their cost per wear.
"Girl Math" was first popularized by the New Zealand podcast Fletch, Vaughan & Hayley. In a July episode that has since been viewed over 1.6 million times on TikTok, the hosts humorously told a caller that her $400 wedding hair extensions were "basically free" because of "Girl Math."
"We're looking at $40,000 to redo the wedding because that hair just looks thin," they told her, whereas the cost of the hair extensions was really only 1.40 New Zealand dollars per inch of hair, or around 80 cents per inch.
TikTok videos posted with the #girlmath hashtag have amassed over 36 million views on the platform since July.
In another episode, the podcast hosts jokingly advised a caller to view a $330 dress as merely costing $110, since she was planning on wearing it at least three times.
One user commented in the video, "To add in another layer: my friend and I do cost per compliment. With enough compliments, the outfit pays for itself."
"If I buy something but then I return it, I've made money," TikTok user Mckennaelianna humorously said in one of the platform's most popular videos about the trend, seen over 11 million times.
Plus, by not buying $50 shorts, you've just "earned" $50, she said. Now, you're free to spend it elsewhere.
"Anything under $5 feels like it's pretty much free. Girl math," Sam James, another user, joked in a video posted on August 3, which has racked up over 3 million views.
"Even like tickets that I buy months in advance, I show up to the concert and I'm like, this was a free concert," she added.
"Boutique gym classes are also an investment because $45 to get yelled at for an hour is actually cheaper than $200 of therapy," user Alyssa Davies said in her video on the trend, "This is just obvious girl math."
While the trend leans heavily on humor, not everyone's laughing.
"'Girl math' is just the latest iteration of us trying to rationalize financial behaviors that we know we shouldn't be doing," financial planner and psychologist Brad Klontz told CNBC in a report published Saturday. Meanwhile, a Fox Business report likened the trend to buy now, pay later financing, where purchasers break down big-ticket items into multiple installments to justify overspending.
Even so, "Girl Math" joins the roster of emerging personal finance trends making waves on TikTok. These trends — like "Girl Dinner," "Bougie Broke," and "Lazy Girl Jobs" — offer users a lighthearted way to delve into money matters that they feel strongly about.
One expert told CNBC that "Bougie Broke" helped dismantle taboos around talking about money, while the TikTok users behind "Lazy Girl Jobs" told Insider that the trend was a way to discuss the importance of work-life balance.