It can be done but often not very satisfactorily.

My daughter did it with a huge oriental and it looks fantastic, she never put a pad under it.

I did it with a big new rug. Works fine.

I did that in my guest room - no problem at all. The carpet is pretty low pile and the rug is a fairly thick sculpted type oriental. I have no pad under the rug. I also have a very short, dense wool oriental rug on the carpet in my living room. That also works fine. I have all these rugs on carpet because I moved from a house with wood floors to one with more carpet. I hope to get rid of the carpet someday when I feel like moving everything again. So then I will need the rugs and in the meantime I can't stand the plain beige carpet.

In another room I have a thick wool runner that covers the width of carpet from the deck door to the wood floor in the dining area. It has no furniture on it that holds it in place so it ripples a bit. I need to find a way to keep it flat.

Thank you - very helpful. My carpet is not low pile. Am looking at a rug that is .375 pile. And i plan to use felt pad as well as caster cups under the legs of the bed. Hope that works!

Why would you want to cover an area rug by putting it under a bed? What sizing bed ar you talking about and what size rug?

King bed. And 8x11 area rug. Rug will show 2 feet around the bed. The room is very dull with no color - brown wooden bed, ivory wall, beige carpeted floor. The rug will add some color/pattern to the bed room

FWIW, I'd start by bringing in color with curtains, bedding and art. Without those items, I don't think just adding color to the floor is going to make much of a difference.

I love the look of a layered rug surrounding the bed. Go for it.

@IdaClaire - thank you, the picture was super helpful. That's exactly the look i was shooting for. Shades of brown on furniture/fabric/wall hanging and then a layered rug with little color around the bed. I will go for placing rug towards the foot of the bed, great idea

I was wanting to do the same, and the colors in that rug are perfect. Do you know where to find it, Ida?