The rules of girl math
Cash isn't real money. If it came out of your wallet instead of your bank app, it doesn't count.
Anything under $5 is basically free. TikToker Samantha Jane put it as "anything under $5 feels like it's pretty much free," and nobody has argued since.
Returns are income. If you return a $50 top and buy a $100 one, the new one only cost $50. Some people go further and treat the whole refund as new money.
Money you loaded onto a card already left. Top up your Starbucks card on Monday and every drink that week is on the house.
Things you paid for a long time ago are free now. Concert tickets bought in March cost nothing by the time the show comes around in August.
Cost per wear makes anything cheap. A $400 bag you carry every day is about $1 a day, which is less than a coffee.
Sales are savings, and savings are money you made. A coat at 65% off in July is money you didn't have to spend in December.
If you didn't hit the free shipping minimum, you were going to lose that money to shipping anyway, so the extra item was free.
The free one in a buy one, get one free deal doesn't count as spending. Neither does anything you call an investment in your future self.
Where girl math came from
Girl math started on New Zealand radio. On July 30, 2023, the hosts of ZM's morning show, Fletch, Vaughan & Hayley, started using it to justify their own purchases, and listeners called in with theirs. Three days later a TikTok by @samjamessssss picked it up, partly as a follow-on to girl dinner, and it got 3.7 million views.
By early September 2023 brands were in on it. Ulta and Five Below made girl math TikToks to sell their sales, and Lane Bryant captioned a Labor Day sale "you call it Girl Math, we call it the Labor Day sale."
Boy math showed up in late September 2023 as the comeback. The first one, from August, was about buying enough toilet paper in bulk to last two years and saving $20. Most were jokes at men's expense, like 5'9" being 5'11" with shoes on, which is basically 6'0", or not wanting to spend $10 on flowers because they'll die. Others were about money, like driving across town to save ten cents a gallon on gas, or buying a $3,000 grill so you'll never have to eat out again. The calculator has a boy math mode, and every boy math receipt ends with one of these.
Is girl math real math?
No, and the people doing it know that. It's a joke about the stories everyone tells themselves at the checkout. Economists have a name for it, mental accounting: treating a refund, a gift card or a bonus as a different kind of money from your paycheck, even though it spends the same.
Not everyone thinks it's harmless. An accounting professor at Loyola University Maryland, J.P. Krahel, called the label condescending and misogynistic, while also saying it won't hurt anyone who doesn't already have a budgeting problem. That's why every receipt here also prints the real math at the bottom.
If you want to argue about whether the whole thing counts as foidslop, there's a vote on that.
Sources
- Girl math, Wikipedia
- Girl math TikTok trend, BuzzFeed
- What is "girl math?" The TikTok trend redefining bad budgeting, CBS News Baltimore
- It's girl math: Ulta, fashion brands cash in on viral TikTok term, Blue Mountain Eagle
- Boy Math / Girl Math, Know Your Meme
