Cost Per Wear Calculator
Cost-per-wear, but make it ✨ conscious ✨
The Girl Math
Calculator
For the girlies who shop with intention.
Justify your purchases — sustainably.
Made by livlite · cost-per-wear, made conscious
Your cost per wear is...
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How it works
Cost-per-wear is one of the most useful ways to measure the true value of a fashion purchase. The maths is simple: cost-per-wear = price ÷ total number of times you'll wear it. A £200 jacket worn 200 times costs £1 per wear — often a smarter buy than a £20 top worn twice.
Our calculator extends this idea with two kinds of justification toggles, blending the humour of TikTok's viral girl-math trend with the principles of conscious consumption:
- Girl-math justifications (gift card, on sale, replaces another purchase) reduce the effective price, on the playful basis that "free money" is real money saved.
- Sustainable justifications (secondhand, ethically made, timeless, resellable) do both — reduce the price and multiply your expected wears, because quality and timelessness genuinely extend a garment's lifespan.
Because multiplying wears drops cost-per-wear faster than discounting the price, sustainable choices naturally produce the lowest numbers — and unlock the best verdicts.
Frequently asked questions
What is cost-per-wear?
Cost-per-wear is the true price of a fashion item, calculated by dividing what you paid by the number of times you'll actually wear it. A £200 coat worn 200 times has a cost-per-wear of £1 — often cheaper in real terms than a £20 top worn only twice.
What is "girl math"?
Girl math is a viral TikTok trend in which fashion purchases are reframed using creative (and often hilarious) logic — like "if I bought it with a gift card, it was free" or "if I wear it twice, it's basically half price." Our calculator turns the joke into an actual tool, with a sustainability twist.
How does this calculator reward sustainable choices?
Each justification toggle does one of two things. Girl-math toggles reduce the effective price. Sustainable toggles reduce the price and multiply your expected wears — because quality, secondhand, and timeless pieces last longer.
Is the Girl Math Calculator free to use?
Yes. The calculator is completely free, requires no sign-up, and runs entirely in your browser. No data is sent or stored.
Which currencies are supported?
The calculator supports British pounds (£), US dollars ($), and euros (€). You can switch between them at any time using the currency selector in the top-right corner.
What counts as a good cost-per-wear?
Anything under £1 per wear is widely considered a smart purchase. Under £0.50 per wear is excellent. Sustainable shoppers regularly reach £0.20 per wear and below by buying quality pieces secondhand and keeping them in rotation for years.