Should I Go To Dunkin Donuts Today?
Published on 2016-02-14

I've come to enjoy coffee (regular and decaf) in my adult life. So do others in the US, apparently. According to the website, there were 108,000,000 (108 million) coffee drinkers in the US. For context, the US population at that time was estimated to be around 272,690,813 (272 million) people . In other words, roughly 40% of the US population drank coffee. That's a big cup of coffee to say the least.

World's Largest Coffee Cup

Since so many of us spend so much time enjoying coffee, it seems like being confident we're consuming it in a cost efficient way would be useful. It made me wonder if:

  1. I can save money by making it myself.
  2. If I can save money, how much can I save?

The gist of it is that I can certainly save if I avoid going out. In fact, it would cost me roughly half (50%) as much to make it at home instead of going out to a specific location to get my coffee.

Firstly, here's where I did the calculations . Feel free to tinker with it and find any mistakes, or switch it to meet your needs. I tried to set it up so that the numbers could at least be changed in case other people see things differently.

I made a few assumptions to help myself work these details out:

  1. I used Dunkin Donuts since that's where I often will end up.
  2. DD grounds from a store will give me equivalent quality to a store-made coffee.
  3. I'm buying a medium hot coffee from DD (which comes out to 14 fl.oz)
  4. I drink one coffee per working day (5 days of a week) and I work 50 weeks of the year.

With that in mind, let's answer some questions:

How much does it cost me to buy my coffee in store?

Using the above assumptions and the estimated market price of a medium coffee near me ($2.29), it's about $572.50 a year.

How much does it cost me to make my coffee at home?

This involves answering a few smaller questions:

How much coffee is required to make a medium coffee at home?

The packaging on a bag of grounds from DD and many other coffee makes suggests roughly 1.5 "scoops" to every 6 fl. oz of water. The packaging also claims that for 12 oz of coffee grounds, one can make 40 cups of coffee (using the info they provide).

To make an equivalent to the hot medium coffee from DD, we'd need about 3.5 "scoops" . I derived this by using the ratio of a medium hot coffee to the suggested 6 fl. oz they suggest, and then multiplying it by the suggested amount of scoops for each 6 fl. oz.

How many medium coffees can I make with one bag of coffee?

Using the information from the section above, there are roughly 17 medium coffees in one 12 oz bag of grounds . There are roughly 60 "scoops" in a bag of grounds ( 40 cup/bag * 1.5 scoops/cup = 60 scoops/bag ). And since we need about 3.5 scoops to make a medium coffee, we end up with 17 medium coffees from a bag of this coffee ( 60 scoops/bag / 3.5 scoops/cup = 17 cup/bag ).

So, how much?

We would need about 15 bags of grounds to survive the year on this system ( 250 cup/year / 17 cups/bag = ~15 bag/year ). Assuming a price of grounds costs about $9.00 (a very rough guess), you get about $135 in grounds.

Of course I'm fancy too and enjoy half-and-half. Assuming I'm an animal and drink a quart of half and half each week, that's 50 containers a year. That comes out to around $125 a year.

So, my total yearly cost for making my own coffee would be ~$260. This is around half the amount it would cost me to buy it in the store.

Are you sure this is realistic?

Of course I could be off base. But I think I've exaggerated the numbers enough to ensure that I compensate for losses here or there. It would be really interesting to try and come up with experiments or data sets to see if what I'm saying is accurate. YMMV.