Just a pet peeve of mine - it seems like it's well intentioned, but for many people who really could use it (people in small spaces starting their own business), it's not applicable. On the other hand, it can cut a nice chunk off of a big house's mortgage.
I say this as someone who has never been able to take advantage of the writeoff despite working from a small home for years.
Here you can write off the entirety of the space if it's used for business purposes, or a pro-rated amount if it's used for any non-business purposes.
Unfortunately, as soon as you step into "pro-rated" the value drops immensely.
If you have a 1000sqft house with a 100sqft office for which you pay $2,000/mo in rent, for a dedicated space you can write off `100sqft/1000sqft * $2,000/mo` = $200/mo = $2,400/yr
If you use that office for one hour once a week to join the video calls of your secret club or something, you can now only claim a fraction of the hours you used for work (160hours/mo) versus _total hours_ it exists (720hours/mo), not total hours you use the room. So the equation changes to `100sqft/1000sqft * 160h/720h * $2000/mo` = $44/mo = $528/yr
Since the denominator is the total hours available for use, not the total hours you use it you're no longer claiming any value for the time you're not using the room.
It's a little disappointing because I do have a spare room I could dedicate to an office, but I also have a nice desk with a nice chair and five monitors, speakers and mic set up for comfortable video calls, etc, etc. The extra tax refund would basically pay for me to re-buy a second copy of all this stuff after a year and I'd be saving money from there on out, but it's just so wasteful.
This year they offered a "simplified" deduction of just a flat $2/day up to $400/yr and so I didn't even bother with the paperwork for the detailed claim... this actually pays me more even though my rent is several thousand dollars a month.
See e.g. https://www.zdnet.com/article/your-home-office-deductions-ch...
With the pandemic there is a flat amount everyone can deduct for 2020.
But that has always been the case. Anything you purchase that is used for work purposes can be deducted (at a pro-rata basis if need be).