Why do we need the ‘girl math’ excuse to buy ourselves nice things?

You know when you buy something that’s a little on the expensive side but you justify it by the cost per wear or use? That’s girl math.

Girl math has been going viral on TikTok this week, with videos featuring #girlmath surpassing 55 million views on the app. The term appears to have originated from a New Zealand radio show segment where listeners call in and explain the ‘girl math’ behind a big purchase.

Some users have called into the ‘Fletch, Vaughan & Hayley’ show on station ZM about purchases including the Dyson Supersonic Hairdryer (£329), a designer tote bag worth £465, and even tickets to Taylor Swift’s Eras concert in Sydney including flights and accommodation (£2,607). The host and the female producers then try and work out how to make the cost equate to “basically free”.

The trend has quickly spread on TikTok with users justifying their purchases and explaining other examples of ‘girl math’. Alyssa Davies, who goes by @mixedupmoney on TikTok, posted a video that has been viewed over 650,000 times where she shares a “list of girl math things I know that are very true in my mind, I could justify them all day and you will never win this argument”.

“If my favourite store is having a sale, I have to buy something or I’m actually losing money,” she says. “Botox counts as an investment in yourself. Boutique gym classes are also an investment because £45 to get yelled at for an hour is cheaper than £200 therapy and I can’t do that every day.

“If I buy a £300 purse and use it every day then it’s going to cost less than £1 a day so it’s basically free. If we go on a girl trip and we agree to split everything, that is budgeting. Also, if we’re on that trip and we get free drinks from anyone or free entry we actually made money, so we can spend more money the next day.”

Users were quick to comment in agreement, with one person writing: “Not spending enough to get free shipping is losing money.” Another added: “If I return something for £50 and buy something else for £100 it’s actually only £50 which is a great deal.”

Girl math appears to be a universal phenomenon as women (including myself) have internal arguments about whether or not a purchase can be justified. We bargain with ourselves, talk ourselves down when necessary, and leave things sitting in our carts for days until we bite the bullet and hit ‘check out’. But, why do we feel like we have to justify these purchases in the first place?

Look, I’m about to go into heavy generalisation with gender stereotypes here, but do we see men using ‘boy math’ to justify their purchases? No. Do we think men spend time thinking about how many times they will use their boat or their new road cycle or their new gaming equipment before buying? Probably not. They buy the things they feel that they have earned or will enhance their life in some way for the better. They don’t feel guilty for leaning into their hobbies or treating themselves to something nice once in a while, so why should women feel like we need to justify our purchases?

Women should be allowed to buy themselves that dress they’ve had their eye on or that nice piece of jewellery for their milestone birthday without having to consider the cost per wear. We should be able to buy it simply because we love it and it will make us feel good.

Of course, I’m not saying spend all of your money on everything you want – you should only ever spend within your means. But, as long as you can pay your bills and any other outgoings and pop a bit away in savings (which may not always be possible during the cost of living crisis), then why not use some of your ‘fun’ money for something you really want?

Girl math is just another mechanism to make women feel guilty for buying themselves nice things, when really we shouldn’t need an excuse to buy that forever handbag, or heirloom piece of jewellery or even the dress that we’ll wear a few times and then sell on Vinted. So lose the guilt and buy the thing, we say – as long as you can actually afford it.