Cost Per Use Calculator
Is the dearer one worth it? Enter the price, how often you will use it and how long it lasts, and see the cost per use and the break-even point. Advanced adds running costs, resale, finance, renting and a chart.
How your cost per use is worked out
Cost per use = everything it costs you over its life ÷ the number of times you use it.
- 1
Count the uses
3 a week × 52= 156 a yearGood pair: 4 years= 624 uses
- 2
Add up the cost
Good pair: 150= 150 in all
- 3
Cost per use
150 ÷ 624= 0.24 a useCheap pair: 0.26Good pair wins
- 4
Break-even uses
150 ÷ 0.2564= 585 usesyou get 624so it pays off
Read more: the formula, worked example, renting and tips
The formula
uses = times a week × 52 (a day × 365, a month × 12) × years it lasts
total cost = price (or total paid in instalments) + running cost per use × uses + upkeep a year × years − resale value
cost per use = total cost ÷ uses
break-even uses = (price + upkeep − resale) ÷ (the other item's cost per use − running cost per use)
uses until it beats renting = price ÷ (rent per use − running cost per use − upkeep a year ÷ uses a year)
Worked example
A cheap pair of shoes costs 40 and lasts 1 year. A good pair costs 150 and lasts 4 years. You wear them 3 times a week.
- Uses a year: 3 × 52 = 156. The cheap pair gets 156 wears; the good pair gets 156 × 4 = 624.
- Cheap pair: 40 ÷ 156 = 0.2564, so 0.26 a wear.
- Good pair: 150 ÷ 624 = 0.2404, so 0.24 a wear.
- The good pair is cheaper per wear: (150 ÷ 624) ÷ (40 ÷ 156) = 0.9375, and 1 − 0.9375 = 0.0625, so 6.25% cheaper. Put the other way, the cheap pair costs 6.67% more per wear.
- Break-even: 150 ÷ (40 ÷ 156) = 150 × 156 ÷ 40 = 585 wears. At 156 wears a year that is 585 ÷ 156 = 3.75 years, or 3 years 9 months. The good pair lasts 624 wears, so it pays off with 39 wears to spare.
- Over 4 years you would buy the cheap pair 4 times: 4 × 40 = 160, against 150 for one good pair. That is 37.50 a year, or 3.13 a month (150 ÷ 48), for the good pair.
Running costs, upkeep and resale
A coffee machine costs 300, lasts 3 years and makes 2 cups a day. Pods cost 0.40 each, descaling and a new seal cost 20 a year, and you sell it for 60 at the end.
- Uses: 2 × 365 × 3 = 2,190 cups.
- Total: 300 + 0.40 × 2,190 + 20 × 3 − 60 = 300 + 876 + 60 − 60 = 1,176.
- Cost per cup: 1,176 ÷ 2,190 = 0.54.
- Against a 3.00 café coffee, each cup at home saves 3.00 − 0.40 − 20 ÷ 730 = 2.5726, so the machine pays for itself after 300 ÷ 2.5726 = 117 cups, in under 2 months.
Paying in instalments
When you pay over time, the calculator uses the total you pay, not the shelf price. The monthly payment is price × r ÷ (1 − (1 + r)−n), where r is the yearly rate ÷ 12 ÷ 100 and n is the number of months. For 1,200 at 12% over 12 months, r = 0.01, so each payment is 106.62 and the total is 1,279.42, which adds 79.42 of interest. At 0% the total is just the price.
Renting or a subscription
A rental is turned into a cost per use: by the use or day it is the amount itself; a monthly plan is the amount × 12 ÷ uses a year; a yearly plan is the amount ÷ uses a year. A 15 a month plan used once a week costs 180 ÷ 52 = 3.46 a use.
Tips
- Be honest about how long the cheap one lasts and how often you will really use the dear one. A great price per use only counts if you actually use it.
- Life in uses suits things that wear out by use, like razor blades (shaves), tyres or printer drums.
- Cost per use ignores what the money could earn elsewhere and any value you place on quality or comfort.
Common questions
How do I work out cost per use?
Add up everything the item costs you over its life (the price, plus running costs and upkeep, minus anything you sell it for) and divide by the number of times you will use it. Shoes at 150 worn 3 times a week for 4 years is 150 ÷ 624 wears = 0.24 a wear.
Is the expensive one worth it?
It is worth it when its cost per use is lower. A 40 pair worn 3 times a week that lasts 1 year costs 0.26 a wear; a 150 pair that lasts 4 years costs 0.24, so the dearer pair is about 6% cheaper per wear, as long as it really lasts that long.
What is the break-even number of uses?
It is how many times you must use the dearer item before its cost per use falls to the cheaper one's. For the 150 pair against 40 ÷ 156 = 0.2564 a wear for the cheap pair, that is 150 × 156 ÷ 40 = 585 wears, about 3 years 9 months at 3 wears a week.
Should I buy or rent?
Buying pays for itself once the money you save on each use (the rental price minus running and upkeep costs) has covered the price. If that happens before the item wears out, buying is cheaper. Advanced mode works this out for renting by the use, day, month or year, or a subscription.
Does selling it later count?
Yes. Anything you get back at the end comes off the total cost before it is divided by the number of uses, so a resale value of 60 on a 300 machine makes it cost the same as a 240 one with no resale.
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