Q: Why is it that when I say I’m working out of my home, I’m actually working at an office in my home?
A: The compound preposition “out of” usually refers to moving from, or being away from, something, and it’s had that meaning since Anglo-Saxon days.
In early Old English, according to the Oxford English Dictionary, “out of” was the opposite of “into.”
The first example in the OED is from a translation of Historiarum Adversum Paganos, a comparison of pagan and Christian times, by the early medieval theologian and historian Paulus Orosius:
“Hie aforan ut of þære byrig hiora agnum willan.” (“They went out of the city of their own accord.”)
In the 20th century, according to Oxford citations, “out of” developed a new sense: working “from (a base or headquarters)” or “using (a place) as a centre of operations.”
The earliest OED example (from Budd Schulberg’s 1941 novel, What Makes Sammy Run?) refers to a prostitute working out of a different kind of house than the one you’re asking about:
“ ‘She’s turned pro,’ I said. ‘She’s working out of Gladys’.”
Most of the OED citations use “out of” in the sense of using a place as headquarters but working elsewhere at least some of the time.
It’s easy to see, though, how the place in question evolved from a headquarters to a primary workplace, as in this example:
“The miscellaneous radio amateurs and visionaries who worked out of shacks and garages.” (From the June 25,1976, issue of the Times Literary Supplement.)
Here are the dictionary’s other examples:
“We were going to run away together. … I could always get work out of Miami.” (From Give the Boys a Great Big Hand, 1960, an “87th Precinct” novel by Ed McBain.)
“Goodall had now started to work out of Devon Concrete to all parts of the South West.” (From a 1993 issue of Vintage Roadscene magazine.)
Finally, here’s a recent example that we found in the June 18, 2016, issue of the New York Times: “My wife and I still work out of our home in South Portland; I’m a writer and she’s a digital strategist for a software company.”
from Grammarphobia http://www.grammarphobia.com/blog/2016/07/out-of.html