If your bedroom is 36' long, why can you only spare 6' of that for the master bath? I'd be much more generous, and take it up to 16' for the bathroom, leaving 20' for the bedroom. Given the position of the door, you'd need to put the bath at the other end, or else make a bit of a hallway going into the bedroom part.

Could we see the whole floorplan?

With the relative location of the toilets, you would need a second stack anyway, so you may have other options.

I agree with weedy, I'd make is wider than 6' ( maybe 10-11') aand incorporate the window into the bath. Hard to say without see the layout of the entire space.

It looks to me that the placement of the bedroom door off the hall is dictating the width of the bathroom.

Thanks for your suggestions about increasing the size of the master bathroom. Unfortunately, I mis-typed. The bedroom is 26' long, not 36' long. Which means that by giving up 6' to a bathroom we've got at 12' x 20' bedroom to work with. Sorry, I should have caught that (wishful thinking?). I include the layout for the entire second floor below. We toyed with the idea of moving the entrance to master bedroom to opposide side of stairs, where closet is. This would give us room to expand both hall bath and master bath. However, someone in town with a similar layout to our house did this a few years ago. While it gets a lot more functional space into the second floor, removing the open area at the end of the hall makes the second floor feel much more cramped than we would like.

We hope the design below makes certain compromises (largely to keep within budget), but remains functional and somewhat spacious. However, there are probably functional issues we're overlooking or a way to work with this space we've missed.

I don't like the position of the sink. I think it really crowds the shower. I'd still steal a little more from the bedroom, just enough to pull in the window. Then you could do 2 sinks like this:

Thanks, Weedyacres. You're right. Layout was too crowded. We tried blocking out the bedroom around the second window, but it felt like that was sacrificing too much light and space from the master bedroom. But we did try expanding the space a bit and moving things around so they don't feel so cramped. The nice thing about the layout below is that the toilet drain will be much closer to main drain and we don't have to worry about the possibility of having to run a new drain line. Does this layout look any better?

MUCH better. And your shower is now 4'6" square, right? That's a very good size for a modest bathroom.

Thanks again for helping us to rethink the layout and your helpful suggestions. The layout seems much more workable now. Have to calculate more precisely, but yes, the shower should be appx 4'X" x 4'6" which should be a good size. We have to figure out if a regular bench or a corner bench works best with the new shower shape, but we do like the idea of having a seat in there.