Discovering that some 16-ounce glass mugs we had recently purchased were not quite as big as we would like, Ms Eclectic and I were delighted to discover these 17-ounce glass mugs on Amazon.
It turns out they aren't really much, if any, bigger than the 16-ounce mugs we already had.
Q. How could 17-ounces and 16-ounces be approximately the same thing?
A. If the 17 ounces are imperial fluid ounces, and the 16-ounces are US fluid ounces.
Roughly, 17 imperial fluid ounces equal 16.334 US fluid ounces.
No foolin'. They are different. See this from Wikipaedia.
An imperial fluid ounce is ... approximately 28.4 ml.
A US fluid ounce is ... approximately 29.6 ml. ...
1 imperial ounce =~ 0.960759940 US fluid ounces
In fact I once knew this difference, after winning an argument over 40 years ago about the comparative sizes of US vs Imperial gallons. I just didn't expect the difference to appear here, and I guess I should have.
From now on, I'll try to stick to millilitres.