👢 Cost per use — what a thing costs every time you use it
A $200 pair of boots worn 150 times is $1.33 a wear. Put in what a thing costs and how many times you will use it, and see what each use really costs — then add a second thing to see which of them is the cheaper one to own.
Results
Side by side
Every bar is drawn to the same scale, so the cheapest a use is the shortest bar and the longest bar is the dearest thing on the list. The pale track behind each one is the dearest.
Each thing, per use
One line per thing: what it costs, how many uses you are counting on, and what that comes to every time you reach for it.
| Thing | What it costs | Uses | Each use |
|---|
What other numbers of uses come to
| Uses | Cost each use |
|---|
The average cost a year, over one to five years
An estimate, not advice, and only as good as the number of uses — which is the one figure here that nobody can know in advance. Halve the uses and the cost of each one doubles; double them and it halves. A rate of use is counted over a year — 3 a week is 156 uses, 3 a month is 36 — so a rate and a total can be compared directly. Nothing else about the thing is in this arithmetic: not what it costs to repair, clean, insure or replace, not what it is worth when you are finished with it, and not the pleasure of owning it, which is the part that cannot be divided by anything. A cheap thing used rarely can cost more a use than a dear one used constantly, and the count has to be honest for a comparison to mean anything.
Why use this calculator?
Some of the best value in a wardrobe is the expensive thing worn constantly, and some of the worst is the cheap thing worn twice — which is impossible to see when the two price tags are side by side. This calculator turns a price into a cost per use, so $200 boots worn 150 times work out at $1.33 a wear against a $60 pair worn 30 times at $2.00. It is the fairest way to judge something you will keep for years, and the quickest way to see that the number of uses decides the answer.
The economics of buying well
Cost per use is an older idea than wardrobes and price tags suggest:
- The boots theory comes from Terry Pratchett’s Men at Arms (1993), where Sam Vimes works out that a $50 pair of boots lasting ten years is cheaper than $10 boots that leak after a season: the poor man spends $100 on boots over the same decade and still has wet feet. The passage is well enough known that the idea is now named after the character.
- The oldest leather shoe anyone has found is about 5,500 years old — a one-piece lace-up with its laces still intact, found in 2008 in the Areni-1 cave in Armenia, preserved by cool dry air and a sealing layer of sheep dung. The same cave held the world’s oldest known wine-making site.
- The threshold is what decides the answer. $200 boots only reach $1 a wear at 200 wears, which is nearly four years of once-a-week use — so cost per use is really a test of how long you will keep something rather than of what it cost.
How does this calculator work?
The arithmetic is one division:
cost per use = price ÷ number of uses
Everything else on the page is that same figure read another way:
- A rate of use — 3 a week, 1 a month — is counted over a year and turned into a number of uses: 3 a week is 156 uses, 3 a month is 36. That is what lets a rate and a total be compared directly.
- Lasting twice as long means the same price spread over twice the uses, so the cost a use halves; lasting half as long doubles it.
- The uses needed to reach $1 a use is the price ÷ 1, rounded up to a whole use.
- Kept for one year to five, "each year" is the price ÷ the years: the same money spread over the time you own it, with every use in those years getting cheaper.
- With more than one thing on the list, the bars are all drawn to the same scale, so the cheapest a use is the shortest bar and the dearest fills its track.
Frequently asked questions
How do I count the uses?
A use is a wear, a wash, a cup, a ride — however you count using the thing. Nobody knows the real number in advance, which is why the page shows what the price comes to at plenty of other counts: halve the uses you hope for and each one costs twice as much, and the count is the one figure here worth being honest about.
Why is a rate of use counted over a year?
So a rate and a total say the same kind of thing. 3 a week becomes 156 uses a year and 3 a month becomes 36, which is what lets a cheap thing you use constantly be compared with a dear one you use rarely. Without that step, "3 a week" and "150" would have no common ground.
Should I include repairs, cleaning and insurance?
Not in this figure: the arithmetic is the price and the count, nothing else. Anything you spend keeping the thing going belongs on top of the price — add the repairs and the servicing to what it cost and the cost a use goes up accordingly, which is the quickest way to find out that a cheap thing was not one.
What about what I could sell it for?
Left out, and that makes this the pessimistic reading for anything that holds its value. If you resell a car or a bike for half of what you paid, the money you actually spent is the difference, so the real cost a use is lower than the number here — subtract the resale value from the price before you put it in if you want that version.
Is the cheaper thing always cheaper per use?
No, and that is the whole point of the page: a cheap thing used rarely can cost more each time than a dear one used constantly. Both figures have to be honest for the comparison to mean anything, and the price alone tells you nothing.
Does it tell me what to buy?
No. It divides a price by a count and compares what comes out. The pleasure of owning the thing is the part that cannot be divided by anything, and a number can tell you that the boots are the cheaper option without telling you that you want them.
What does the share button actually send?
The sentence on the result card and a link to this page, and nothing else. The site sends nothing anywhere by itself: the button hands that sentence to your own device’s share sheet, or puts it on your clipboard when the device has no share sheet to offer. What you do with it after that is between you and whichever app you picked.