There are 3 sizes which will work. Gives you some leeway when shopping.

Install: 30" over nightstand.

Any area rug could cause tripping. Get a good pad; or get a rug with a non-slip backing.

@elcieg Thanks! Your diagram is super helpful. Looks from the pics like the rug should not go all the way against the wall at the head of the bed, is that correct? If so, then I assume it means the nightstands won't sit on the rug either? What if the front legs of the tables sit on the rugs but the backs don't?

I'm also considering placing a chaise lounge that I already own along the foot of the bed. Do you think the rug should go under that as well?

To keep nightstands level, place all legs on the floor.

Do you mean a settee or bench, as a chaise lounge is not going to look good. Unless you are buying a small rug, if you pull down enough it will sit on the rug.

For help with decisions, on line images on Houzz and Pinterest could be helpful.

Since you have to cover more than just the area under and around the bed for the 80% rule, I would get carpet cut to the exact size you need to cover the area and have the edges bound. Most carpet comes in rolls 12' wide, so maybe 12' X 16' (approx.) would work. You don't have to go under the nightstands and you have that cut corner at the other end of the room you have to work around. Hopefully you can find a remnant that works as that would be less expensive. 12' X 16' is not a standard area rug size, so you won't find anything off the shelf that size.

Will the room look bigger or smaller if the rug touches the wall behind the headboard or if the rug begins in front of the night stands? (Did that make any sense at all???)

@kandrewspa . I'm totally going to cheat on this one and go nowhere near 80%. (The neighbor below me has her 22 year old son living in the bedroom underneath this room. She is fine with noise being made in here as she thinks it will encourage him to find his own place sooner. Love it!) But, I do think it is good to at least cover a decent chunk of the bed area floor. Would 9 x 12 work here or look odd? It seems to be a standard size.

@Maureen It is indeed a petite chaise lounge. It might not be ideal, but at close to 100 years old and in perfect condition, I think it will outlast any kind of bench or settee I would buy today. We've used it at the foot of the bed in other guest rooms and people are in love with it. It was in my grandma's bedroom when I was a kid. I remember sitting on it while she got dressed and my mom was trying to teach me how to blow bubbles with orange Trident gum.

Figure out how a 9 X 12 would hit the desk. You don't want the desk partly on and partly off the rug.

Sounds like a precious piece. Was suggesting elsewhere (not replacing) as they are most often seen by a window or in a corner.

@Maureen - I'm smitten with the picture you posted. Perhaps there is space by the window.

@palimpsest - I feel like a braided jute rug is the way to go with messy guests because they are so inexpensive, people are always hocking large new ones on Facebook Marketplace for a few hundred bucks at most. Do you it matters which way the lines of the weave go - parallel or perpendicular to the bed?

I might look for a threadbare Persian where pattern hides a lot and they can be spot cleaned. I have 50- 100 year old rugs that are really bald that still look pretty good.

@Kendrah, all four table legs should be on the bare floor; the rug should be 3/4 under the bed around.

If the chaise works into your scheme, sure, your parents may like to stretch out and read. So add a floor lamp. You could add a pharmacy lamp to match the wall sconces.

Take a look at this rug. Comes in lots of sizes; the 9 x 12' is $123 .00; there are 12 colors; and thousands of positive ratings; describe as an indoor/outdoor, so roll it up and take it outside and hose it clean.

Nourison Essentials Solid Contemporary

https://www.amazon.com/dp/B08KJGFW6X/ref=twister_B0BVJNDKJP?_encoding=UTF8&th=1

If you are still thinking of the jute, there are sites you can search "washable jute" . If you find plain old jute (I love the color with the headboard fine),, there are different textures. Some, surprisingly, are quite soft under foot. The larger the loop, the softer the rug. Amazon, again, at a good price point.

Forgot your other question. The top of the headboard, should be 28" above the top of mattress for a queen.

If you are a rule follower? Eighty percent of the room sq feet is 224 sq. feet. of the whole 280. You need a 12'6" x 16/17' rug, close enough. There's no such thing ready made. That will leave NINE inches exposed on the long wall sides, both. Check the length as you have an angled wall, meaning you need to know that angle.

Have broad loom cut/bound to those dimensions....or get two rugs.

Which WILL be more a hazard for tripping, and especially for a desk and chair .

@JAN MOYER - I’d hoped you’d weight in. Wjat are your thoughts on headboard height above mattress?

Thanks for you calculations. I’m not going to be a rule follower. But seeing the size you calculated makes me feel better about doing a 9x12. Which direction should it go? Entire headboard and side tables on the rug I presume?

@palimpsest I love a good threadbare Persian rug but they are soooo much more expensive. I’m going for bang for my buck here.

Get a 10 x 14 and place it logically....... your ROOM is 14 feet wide and 20 LONG.

You don't need it UNDER the side tables, you feet can not step under there, right?

!0 x 14 better suits the space. You'll have more coverage, and there will be 2 feet exposed on the LONG walls, uncovered by rug

Will do Jan. Thanks!