How many clothes should you own? The maths behind a sustainable wardrobe

The environmental impact of a garment often depends on how many times it's worn. Every additional wear helps "offset" the garment's carbon footprint. (Adobe Stock: Wayhome Studio) Link copiedShareShare articleMost people suspect they own too many clothes, but they aren't sure exactly what the "right amount" is. Recent wardrobe studies, in which researchers literally peek inside people's closets, show the scale of the problem is far greater than most of us imagine. Sixty years ago, the average person owned about 40 garments. Today, that number has more than quadrupled, with a recent study revealing these numbers continue to trend upwards. The typical wardrobe now contains an average of 199 major pieces. Even more striking: 25 per cent–50 per cent of these items are languishing in the back of drawers and rails. Research tells us this is not just a clutter issue — it's a carbon one. Every garment carries a sizeable environmental footprint long before it reaches a hanger, including from fibre production, spinning, weaving, dyeing, cutting, sewing, packaging and global transport. A jacket that ends up as fashion waste is more than a label and price tag. It's the sum of all the resources and emissions that brought it into being. At the same time, donating excess garments to charities is rarely a solution. Before you channel your inner Marie Kondo and bag up half your wardrobe, it's worth knowing that most charities are overwhelmed, and only a small fraction of donated clothing is resold. The rest often ends up in landfill or exported overseas, shifting the problem, rather than solving it. The real issue isn't simply how much we buy, but how little we wear what we already own. UK fashion designer and PhD student Wendy Ward has conducted audits into how often she wears her clothes. (Supplied: Wendy Ward) One of the clearest findings emerging from sustainability research is that the environmental impact of a garment often depends on how many times it's worn. In a sense, every additional wear helps "offset" the garment's carbon footprint. The European Union has calculated the minimum number of wears needed for different clothing types: For many people, these numbers may be far higher than expected — and they shift the sustainability conversation from "buying better" to "wearing more". My own recent research has gone further by offering a simple mathematical model to calculate how long it takes to reach these minimum wear counts. The formula is straightforward: wearing frequency x wardrobe volume. The results are eye opening. How many items of clothing do you own, and how often do you wear them? Experts want shoppers to use this knowledge to fight the fashion churn destroying the planet. Take dresses. The average participant in the study owned 23. So if they wore a dress once a week, it would take nearly 31 years to wear each one 70 times. If they wear dresses five times a week, the timeline drops to six and a half years. The maths makes the issue clear: there is no universal "right" number of clothes. A sustainable wardrobe depends entirely on how often a person wears what they own, which is influenced by factors such as seasonality, climate, lifestyle, laundry habits and personal style. The maths also becomes more complicated when you look at the entire wardrobe, rather than a single garment type. Because of this complexity, it's difficult to declare a fixed number of garments that constitutes a sustainable wardrobe. As such, the next phase of my project is the development of an interactive wardrobe calculator — a tool designed to help individuals understand their own clothing use patterns and calculate a personalised sustainable wardrobe size. What the research makes clear is that sustainability isn't about owning the perfect number of clothes. (Supplied/ Baptist World Aid Ethical Fashion Report) The Paris 2030 Agreement to stay below 1.5°C of global warming recommends 85 garments or less would be a responsible target — although imposing strict limits does not take individual wearing patterns into account. People need a practical, tailored approach that reflects their real lives. What the research makes clear is that sustainability isn't about owning the perfect number of clothes, or purging half your wardrobe. It's about understanding the maths behind what you own, how often you wear it, and how those choices shape your environmental impact. Alicja Kuzmycz is a lecturer at Torrens University Australia. This piece first appeared on The Conversation. Copy linkFacebookX (formerly Twitter)PromotionTop Stories'Probably hate me': Finally free and clean, Scott Miller opens upTopic:Swimming

How many clothes should you own? The maths behind a sustainable wardrobe

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