How Big Is a Coffee Cup? The Answer Isn’t Obvious

The standard serving size that Mr. Coffee arrived at was a 5-ounce “cup,” about the size of a British teacup. Though this may seem small now, it actually did correspond to the size of the cups people used for coffee at the time, Esposito says.

It’s also the size that Esposito, a native of Italy, still considers “reasonable.”

Blame It on the Mermaid

You can demarcate coffee cups in America into two periods: B.S. and A.S.

Everything began to change in the late ’80s, Esposito says, somewhere around the time a former Xerox salesman named Howard Schultz decided to take a Seattle-founded coffee shop onto the national stage. After Starbucks, coffee cups got bigger.

“They created their own language for all of their drinks and sizes and everything. So a ‘small’ to Starbucks is really kind of like a ‘large’ everywhere else,” says Jemison, the Portland coffee machine salesperson.

“From my memory, until Starbucks, most of the coffee drinks were reasonable. I mean, the cups were a reasonable size,” Esposito confirms to WIRED. “And then the larger sizes were introduced.”

Photograph: monticelllo/Getty Images

It’s probable that mug inflation had already begun prior to the Venti diaspora. But as Starbucks expanded in the ’90s, Esposito says, other local cafés felt the need to compete. The café cups got bigger, and so did her customers’ perceptions of how big a “cup” is.

Now, when customers arrive at Fante’s to get a coffee maker, she has to stop to explain that a coffee-machine cup doesn’t correspond to a measuring cup, and it also doesn’t correspond to the cup her customers actually drink coffee out of.

“When people come in and ask for a coffee maker and they look at ‘12 cups,’ we automatically explain, ‘That’s not the size of, you know … 12 of your cups,’” she said.

Just Double It

But even though we drink coffee cups about twice as big as we used to, coffee maker companies have no particular incentive to change their cup sizes. Doing so would make their machine look half as big as it used to be, and half as big as competitors’.

The math, instead, falls on you: You’ll need 2 “cups” for one serving, at least if you drink out of a 10-ounce or so coffee mug that’s now considered standard. It’ll take 4 cups, however, to fill a Yeti mug or one of those Stanley beer steins some folk like to drink coffee out of these days.