If I pay for it in cash, it’s free.

every “girl math” video on TikTok and YouTube.

“Girl math” started as a viral trend on TikTok and gained popularity as women (and men) share how they rationalize their spending habits. Many of the videos are just for laughs, but the ideas they present can have a significant impact on your finances, both good and bad.

So, let’s take a look at what girl math is and when you should and shouldn’t use it.

What Is Girl Math?

The term “girl math” is often applied to any technique used to rationalize or defend purchases. This can include big, expensive purchases and smaller ones. The term doesn’t have a fixed definition and is evolving as it is used.

While “girl math” is frequently used to defend unnecessary purchases, there are elements of legitimate budgeting and spending strategies within the method.


somehow it makes sense #girlmath 🤷🏼‍♀️

♬ original sound – kenna 📚🍷

The most consistent theme of girl math is the attempt to define purchases as free.

Here is a list of ways purchases are rationalized as free:

  • Paying with cash
  • Paying with gift cards
  • Paying with preloaded money apps (i.e., Venmo, Paypal balance, etc.)
  • Paying with a preloaded rewards app (i.e., Starbucks rewards app)
  • Buying heavily discounted products
  • Purchases under $5 or $10
  • Purchases made with funds gained from returning previous purchases
  • Purchases paid for months ago (i.e., event tickets, flights, etc.)

Making “free” purchases isn’t the only element. Here are other spending/savings ideas commonly presented in girl math videos:

  • Only cost per use matters
  • Discount purchases make you money
  • Not using discounts or BOGOs (Buy One, Get One) is losing money
  • Not buying something makes you money
  • Only winnings count
  • Returning stuff makes you money
  • Average spend is more important than total spend
  • Round down purchases

While some videos present additional or different ideas, the ideas/perceptions above are the most common.


justifying our purchases with GIRL MATH 🧐🥲 #girlmath

♬ original sound – CAS MAZZUCCO

Applying Girl Math

Let’s look at an example to understand how girl math looks in the real world.

Expenses for a day💵
Top up your gas tank$40
Get coffee$8
Lunch with coworkers$15
Snack from a vending machine$2.75
New outfit$120

Now, let’s apply the ideas behind girl math to this day’s expenses.

Expenses for a day 💵
Top up your gas tankpurchased with a gift cardfree
Get coffeepurchased with the Starbucks rewards appfree
Lunch with coworkerspaid with your Venmo balancefree
Snack from a vending machineunder $5free
New outfit
TopReturned for a different sizefree
Bottoms50% off, original price $60Made $30
ShoesEstimated use of once a week$1.15 per use
ConcertPaid for 4 months agofree

The result is not just less money spent but an actual “gain” of $28. Yes, this scenario is a bit extreme, but it accurately illustrates the perception of how spending is perceived when using girl math.

What Are the Dangers of Girl Math?

The biggest danger of girl math is the disconnect with how much money you are actually spending.

☕️ For Example

Buying a $4.50 coffee daily for a year totals $1,642.50 – so definitely not free.

The girl math way of thinking can make it challenging to come up with any kind of realistic budget and stick to it. How do you track your expenses if you view everything as free?

Another big sticking point is the inherent danger of cost-per-use breakdown. This is especially true with expensive purchases.

💸 For Example

Let’s say you set a $300 budget for a new item (handbag, phone, coffee table, etc.) But the item you want costs $800. So you justify the purchase with girl math.

$800 divided by 365 days is $2/day.

While $2/day sounds great – you’ve just spent $500 more than you budgeted.

When Should You Use Girl Math?

While girl math may not be the best choice for everyday spending, there are some situations where it has advantages.

Discretionary spending would be the major one. Using girl math for purchases is fine if you have already budgeted X amount of money for discretionary spending.

👖 For Example

Let’s say a pair of pants costs $30, and there is a buy 2 get 1 free sale.

  • If you buy one pair of pants, you are paying $30/per pair of pants.
  • If you get 3 pairs of pants, you are paying $20/per pair of pants.

This girl math purchase makes sense if you have at least $60 budgeted for clothing expenses.

Using gift cards or return items to make purchases can also be a valid way of stretching your budget. These purchases really are free, especially if the original item or gift card was given to you.

Another valid idea of girl math is the cost-per-use idea, but only when comparing purchases.

💅 For Example

Let’s say you have $100 to spend, and your options are a mani-pedi, a new pair of shoes, or dinner with friends.

  • Dinner – lasts a few hours
  • Mani-pedi – lasts a few weeks
  • Shoes – lasts a year+

Looking at a purchase this way shows there is more value (at least financially) in purchasing the mani-pedi or the new pair of shoes than there is in dinner with friends.

Cost-per-use can also be a good way to compare different price points. For instance, you can buy $20 jeans that wear out in a few months and need to be replaced, or you can splurge on $50 well-made jeans that last you several years.

“Girl math” is often lighthearted and can just be a way of joking about spending. If you’re keeping to a budget and not piling up debt, a bit of girl math won’t hurt and could help. If those “girl math” hashtags are covering up serious overspending and a growing pile of debt, the joke isn’t funny anymore. It’s time to make changes or even look for help.

Alternatives to Girl Math

If the girl math way of looking at your finances is not working for you, there are plenty of other budgeting methods you can try.

Envelope System

The envelope system consists of creating specific budget categories and setting aside cash in envelopes for each category. This method recently saw a surge in popularity and was rebranded as cash stuffing.

The envelope system has a few similarities to girl math. Preloaded rewards accounts are essentially a sort of digital discretionary spending envelope. This can make this budget method an easy-to-adopt alternative to girl math.


For those looking for a simpler budgeting method that provides overall guidance, the 50/30/20 method might be a good option.

This method breaks down your budget into

  • 50% necessities
  • 30% discretionary
  • 20% savings/debt repayment

Using this method, you can still apply the girl math principles to your 30% discretionary spending while ensuring that your necessities like rent and utilities are paid.

Zero-Based Budget

This budget method is the opposite of the idea that purchases are free. This budgeting method helps you allocate each dollar you earn. Essentially, the goal is to end up with $0 unaccounted-for money each month.

If you’ve previously gotten carried away with spending or lost track of where your money is going each month, this method can help you get back on track.

DIY Budget

When looking for new budgeting ideas, you don’t necessarily have to pick a method right away. Instead, start tracking your spending now, determine your spending categories, and decide where you want to be.

Then, you can choose the budgeting method that works for you. To get a better idea of how to get started, check out our article on budgeting basics.

🤔 Learn more: Understand the impact of structured finance with our post outlining the core advantages of budgeting.

The Gender Question

This article wouldn’t be complete without mentioning the elephant in the room: the idea that the term “girl math” supports the perception of women being bad with money.

In reality, women are not inherently worse at finances. In many ways, women are beating out their male counterparts.

For instance, credit scores between men and women are nearly identical. Men tend to carry more debt than women. Furthermore, women are more likely to use debit cards than credit cards and are better at following budgets when compared to their male counterparts.

The thing is, the rationale behind girl math isn’t exclusive to girls/women. Plenty of boys and men are out there using the same ideas to rationalize their purchases.

I.E., spending money on a golf course membership by defending how often you’ll use it or telling a significant other that an item only costs $100 when it really costs $130 (or much more).

The girl math videos on TikTok, YouTube, Instagram, etc., are not meant to be taken as an attack on gender differences, nor are they designed to impart actual financial advice. These videos are just light-hearted entertainment.

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