'Girl Math' Is All the Rage. But Can It Actually Help You Save?

When it comes to personal finances and money management, I think we all have a few little tips and tricks to make it easier. For example, I'm a big believer in the philosophy of "pay yourself first," which means putting aside money you're saving as soon as you get paid, and treating savings contributions as a bill you must pay rather than an afterthought. That way, money hits your savings account as soon as you get it, and you're not left scrambling to find cash to save at the end of the month.

One set of tricks that has recently gone viral thanks to TikTok is called "girl math." Let's take a closer look at this trend, and assess whether it can actually have a positive impact on your finances and bank account balance.

What is girl math?

Women have an absolutely staggering influence over the economy -- according to Cake Ventures, we control or influence a whopping 85% of consumer spending. Unfortunately, women are also often stereotyped as being less financially savvy or more inclined to spend money in frivolous ways. "Girl math" is a tongue-in-cheek way of describing the very real thought that goes into a lot of spending decisions women make.

One example of girl math is the thought that if you return a purchase you made and your credit card is refunded, you actually made money on the deal. Or if you take a vacation or attend an event that you paid for months ago, it's free (since the act of shelling out money on it was a while ago). Or if an item is on sale and you don't buy it, you've actually lost money. Or anything that costs less than $5 is free.

Many aspects of girl math are silly, but there are actually a few gems buried there -- and a few potentially dangerous money moves.

Where girl math works

One aspect of girl math that is absolutely worth taking to heart is the concept of cost per usage. Let's say you're considering whether to spend $400 on a dress. If you know that you can wear the dress to four upcoming events/occasions, you've got a per-usage cost of $100. That's already sounding more reasonable. And maybe you can then list the dress for sale online and expect to make at least $100 on it, making one of the times you'll wear it free and reducing your all-in cost to $300.

It's always worthwhile to calculate how much use you'll actually get out of a purchase -- and if you'll get more or better use out of the more expensive version of an item, that could make it worth the money spent.

Using girl math to justify small purchases (more on that below) is also solid. Remember, your morning latte is not the reason you can't afford to buy a home, and if spending a small amount of money on something you enjoy makes you happy, there's nothing wrong with that. Spend more of your mental energy focusing on the big money questions -- such as housing and transportation costs, and how to increase your income.

Financial guru Ramit Sethi is a big proponent of this way of thinking. Stress less over that $5 latte and instead fight for the raise your employer owes you and make sure you're saving enough for retirement or any other goals you've set for yourself.

Where girl math doesn't work

Girl math isn't all gold, however. The notion that cash doesn't count as real money can certainly be a dangerous one, especially if you do a lot of your spending in cash. While it is true that debit and credit card spending comes with a "paper trail," it's important to remember that cash spending still counts and if you go overboard, it can negatively impact your finances.

Similarly, if you spent money on something in the past, it hasn't somehow become free. And a sale at your favorite store doesn't mean you lose money if you don't buy something. Money returned to you when you return a purchase hasn't put you ahead -- it's just gotten you out of the red.

Ultimately, getting in the habit of spending money intentionally (even if it's on purchases others might consider frivolous) can make you more mindful and also help you budget. Those $5 coffees you treat yourself to should ideally be figured into your budget, so you know how much they're costing you and can plan for it.

Like any other viral trend, proceed with caution

The idea of girl math is a fun one, and I've definitely had conversations with female friends and colleagues in the personal finance space about how we justify our spending to ourselves and others. But take girl math with a grain of salt, and ensure your purchases of all kinds are adding to your life in positive ways.