Have you ever used a mental shortcut when weighing up a purchasing decision? Maybe you've discounted the cost of a dress by 50 per cent because it does the work of two pieces of clothing.
These rules of thumb are known as "girl math" — and young women across the globe are explaining the mental gymnastics they use to soothe away spending guilt on social media.
It's mostly tongue-in-cheek, delivered with a healthy dose of self-mockery. But, as they say, many a true word is spoken in jest.
Some of the examples of "girl maths" clearly don't stack up from a financial perspective. For example:
- The idea that anything you buy with cash is free as long as there's no receipt.
- That buying something on sale means you "made money".
- That buying extra items online makes sense if you qualify for "free" shipping.
However, there are some examples that are actually useful.
Alyssa Davies is a Canadian influencer and self-described "money nerd" who posts on TikTok under the handle MixedUpMoney.
In a viral video (which is no longer up on her account) she discusses how a $300 handbag used every day costs less than $1 a day — and is therefore "basically free".
While "free" might be stretching the truth, this cost-per-wear basis can be a valid way to evaluate items you use a lot.
The mental calculation that can save you money when buying clothes
Being a savvy consumer doesn't mean buying the cheapest thing possible — and "cost per wear" can help you find a true bargain.
A $100 shirt you wear 100 times is more cost effective than a $20 shirt you wear once then abandon to the depths of your wardrobe. The former is $1 each wear, the latter is $20 a wear.
It's something to keep in mind next time you're thinking of buying from a fast fashion label that doesn't make clothes that last.
Consider the cut, quality, ease of care, what you already own and the fit with the rest of your wardrobe before you buy something new. You don't have to shy from the more expensive option if you'll get exponentially more wear out of it.
Of course, the Holy Grail of this example is the $20 shirt you wear 100 times for 20 cents per wear, which is why I spend so long combing through the sales racks searching for one.
How to avoid blowing your budget in the post-Christmas sales
Every marketing trick in the book is rolled out at this time of year to convince you that you need this thing right now before the sale ends.
This drives impulse spending, a vast waste of Earth's finite resources because such items often end up in landfill.
If we want to do the right thing by the planet, we should buy as few items as possible and make them last, so please consider buying gently used second-hand items or renting instead of buying new.
You might also want to keep your overall budget healthy by setting a limit for total non-essential spending.
Why the 'girl math' trend isn't all bad
Many people have shared their stories of "girl math" as light-hearted humour — but it hasn't stopped some commentators from using the trend to label women as being frivolous or foolish with money.
Dr Tracey West, a financial literacy expert and manager of Talk Money, takes a different view.
"What I like about it is that women have taken ownership of something traditionally and stereotypically the male domain of maths," she says.
"It is critically important for women's economic empowerment that women and girls connect to maths, and say with some confidence that they 'do' maths."
The trend has also encouraged women to talk about purchasing decisions and their personal finances with friends and family, Dr West adds.
Besides value for money, Dr West says there are other factors to consider when making a purchasing decision:
- What else could you do with this money?
- Have you checked your bank account/credit card balance?
- Is this purchase good for the environment?
- How might you feel tomorrow about this purchase? And who is influencing you to buy this?
From fashion to financial empowerment
Ylva Baeckstrom is a senior lecturer in finance at King's College London. She hopes the "girl math" trend encourages women and girls to engage with money and finances.
"It has started a widespread debate about personal finances spread across nations and generations. [But] like so many things in life, it is not perfect," Dr Baeckstrom says.
She hopes the increased discussion about financial decisions could encourage women to feel empowered and in control over their finances — and prepare them for the often-daunting world of investing.
"The step from thinking about the investments you make for your wardrobe to applying these analytical skills to building a portfolio of investments is very small," Dr Baeckstrom says.
"It can be more complex to understand fashion and economise for that than investing your hard earnt cash."
Lacey Filipich is a financial educator and the author of Money School.
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