My suggestion would be to decide what size/amount of furniture you want/need in each space. Then, leave the appropriate dimensions for comfortable walkways, distance from fireplace, major traffic pattern areas, room for patio doors to open, etc. That should give you some idea what dimensions you will need.

I did read something in Sarah Susanka's books (probably the first one, Not So Big House) about rooms/spaces being more comfortable when rectangular and in a certain proportion, more than square footage. You might want to check out the book, to see if it helps you with your plan :)

Entry:None enter into dinning rooom
' Living Room: Ours is 12'8 by 19' 6". A little wider would be wonderful. Maybe 15 wide.

Kitchen is 12' by 11" wrap around counters. Love it good size.Dinning room same as kitchen. I use it differently then dinning room but it would be fine with average table and buffet or china cabinet.

Master Bedroom:14'6" by 12' 8" perfect size. I know maybe a little large but I love this size for us.

Master Bathroom:8' 12' 6" I like it large. Was supposed to have garden tub in it and I had them leave that out to be able to just have the open space.

Child/Guest Bedroom:9' by 13' and I wish it were another foot wider but it is what it is. There is no closet in that room.

What would be guest room is 10' 6" by 13' I use it as my studio.

Child/Guest Bathroom: I think it is 5' by 6' Small but is fine for guest.

Laundry:7' by 6' and the furnace is also in there so I think it is too small. I like a large laundry. But it is fine and serviceable.Never measured it this is a guess.

Mud Room: We use the master bath as the mudroom as there is a door to the outside in it. No other mudroom except the laundry room.

Reach in closet: Hall closet is 5 by whatever reach in depth usually is. Not deep. Reach in in my studio same depth and I think 7 foot wide.

Walk in closet:Master is 5' by 6'

Other (please share what this would be):None Small garden shed. We do have a 8 by 26 or so front porch covered. I do like it. And it is on full foundation and could be closed it easily. Probably will leave it open. Or maybe close in jusr half of it.

Garage/Carport:30' by 30' with 8' by 30' loft and added carport on side of 10' by 30'

Here is a link that might be useful: Floor plan. The kitchen cabinets are not exact as shown and measurements are not right but close.

The floor plan shows an entrance in the living room. That now goes to our side yard it is not our front door. Supposed to be but we turned the house end way on the lot so the front porch is the front entrance.

Entry: No entry specifically INSIDE, but we have a 4 x 4 covered stoop outside. Our front door opens on the living room.

Living Room: 13 x 15 with a fireplace. We removed a 5' wide set of French doors into the dining room and will be replacing them with a set of BIFOLD french doors so the LR can become our guest room. NO closet in the LR.

Dining room: 12 x 12 and is the next room after the LR.
It has an arched door leading to a tiny central hall about 4x 8 which connects the two bedrooms and a really tiny 3/4 bath is in between with a pocket door. The dining room is a passage way and not in a good way. I'll be changing this when we redo the kitchen.

Kitchen: the original dimensions: 12 x 7 and it was way too small. As a temporary measure, we weatherized the back porch (a step down of 4" in floor level) which measured 6 w x 14 long and will be added to the kitchen when we remodel. So that would make the NEW kitchen 13w x 12 long + a laundry area for stacking laundry just inside back door.

No separate laundry area. Front and back walls of kitchen coming down to take in porch and keep dining room from being such a funnel for traffic flow.

Master bedroom: currently 12 x 12. We will be adding to it in the kitchen remodel, so it will then measure 12 x 18.

Master bath: recently added and it is 8 x 12 with a free standing slipper tub and a stained glass window.

Walkin master closet: 5.5' deep x 12 feet long. Not as efficient as it could be, because I wanted light coming into the room and we'd lost two windows when we added on this closet/tub bumpout to the house.

Kid/Guest bedroom: 11.5 x 11.5 I think. We use this as our study/computer room/library/TV room. No bed in here, because we have more demands for the space. Any guests can stay in the living room which presently we do not use often, except as passage to front door or to sun porch.

Reachin closet: 2 feet deep x 7' long, with two sets of fixed louver bifold doors separately hinged to open fully. This closet is in front bedroom, which is now our "study."

Other spaces:
1. Sun porch 10 x 10 which has 3 totally Lexan walls to enclose an old screened porch--rebuilt like a fortress by my DH. Lovely room on south side of house off living room.

2. 10 x 12 wooden deck off the kitchen where we eat in pleasant weather. It is about 24" off the ground.

3. Teahouse formerly a garage 22 x 25 with a 8 x 22 loft at one end, open to the roof elsewhere and Lexan roof except for the front which is standing seam metal. This is my studio/greenhouse/storage space until after our remodel of the kitchen.

I will be building in 2 or 3 tall cabinet pantries when we redo the kitchen. Plus adding a closet in one end of the hall for cleaning/vacuum/mops/brooms/etc by changing the entry to the Master BR to another location near the laundry. This will have the effect of making the other bedroom (now our study) a second private master suite.

Note only two bedrooms, but two baths.
Our current space under the roof, heated and a/c, is 1000 sq ft. Not a big house by any standards, but adequate for a couple or even for two roommates who choose to have separate bedrooms and baths.

I think it depends on the size of the family living in a place.

I live alone (the puppy will join me in the near future - she still chews).
my LR/DR combo is 13 x 24 - that is fine for me but would want it much larger - or 2 separate rooms w/ kids. i had a house once w/ a combo like this but it was more like 16x 30 and had an entry way off of it.

I do like to have an entry but I don't in the new place - which is ok since it's just me and I'll use the back door mostly - thru the utility room.

my mstr bdrm is a good size (for 1 and a dog) it's - 13x13 not counting the closets. I have 2 closets @ about 5 x 4.5'. They are on either side of a hall that leads to the bathroom which is 7 x 13'.

then I have 2 bdrms 10 x 12 (that includes the closet that's about 2 x 7'. and 1 that is 9 x 12' and I'm taking out the closet to make it a tv/computer room.

the kitchen is about 9 x 11'. it seems bigger because it's open on the south side to the hallway.

utility room is about 7 x 8 - again fine size for 1 or 2 people. the laundry will be in there eventually and I'd need more room if I had kids laundry again - or it couldn't be used for anything else. since no kids here now this room will also house a storage cabinet that's 5x 2 x 1 for tools/garden stuff and some dog stuff. the center area will be open for the dog. the furn is in there also.

the hall bath is 5 x 10'. I'd consider it small if more than 1 kid was using it. otoh, while raising my kids the 3 boys and my X shared a bathroom about 7 x 7 and dd shared a bathroom w/me that was about 7.5 x 12. in another house I shared a bathroom w/ the 2 younger kids (main floor bath) and the kids had a half bath upstairs.

I think kid bdrms are good at maybe 12 x 12. they can do ok in a 10 x 12 tho. 10 x 10 should be fine for a guest room.

I'll have about 1400 sq ft for me (and the dog) - and that's about right for me (us).

I do wish I had a garage tho - am hoping to get at least a shed this coming yr.

be sure you have plenty of storage space!

The placement of H/AC floor vents, doors and windows can seriously impact furniture placement.
My full bath is only 5x8. I would love to have it be a little larger.

I agree with LL that it depends on what furniture you want in the room and how you plan on using the room. But I'll give you ours and add comments about them.

Entry: Was originally 5x5 and that was just fine. Just enough space to put up coats and shake off water before entering the living room with wood floor.

Living Room: 12x16 Really a little too narrow. If it were square, it would be a lot easier to arrange furniture.

Kitchen: 10x21 Nice big size, but again, it would work better if it were a little more square.

Dining Room: Ours will be 10x13. I think that will be too small but I was outvoted.

Master Bedroom: 11 x 14. Would be better if it were even one foot bigger, like 12x14. 14x14 would be wonderful. But we have a lot of bedroom furniture. I'd even like this size better if I could put the bed on the short wall instead of the long.

Master Bathroom: 5x8. Small, but works fine. Easy to heat in winter.

Child/Guest Bedroom: 10x10 Kind of small for kids but really too small for overnight guests.

Child/Guest Bathroom: Same, 10x10

Laundry: 6 x 7 - really a hall, but it works for us.

Mud Room: Don't have one

Reach in closet: Master is 5' wide and that is much too small for 2 people. Now if each of us had a 5' closet, that would be great. The guest room closets are 3' and that is ridiculously small for kids.

Walk in closet: Don't have one now. Last house had 8x8. It was wonderful.

Other (please share what this would be): Office space? Seems like everyone wants that now. Ours is too big, 9x20. 8x10 or 10x10 would work great for one person I think.

Garage/Carport: Originally, ours was 22x21 with one double door. It was hard to get both car and pickup in there. Now it's 27x35 and that includes that office space, a bathroom, and a closet. Still leaves us plenty of room for both cars and workshop space.

I made a mistake on the laundry room and guest bath sizes. they both are 8 foot wide. Guest bath is five foot across and laundry room is 7' 6 " across.

Agree with you Marti in a narrow living room More square in any room is better.

"The placement of H/AC floor vents, doors and windows can seriously impact furniture placement."

I've always thought this also. I don't think women are doing the designing!

I really lucked in on my new place - the floor registers are in fairly decent locations. I couldn't believe it! I don't think any of them will mess up my furniture placement.

I've thought that about floor registers too. We have them in the ceiling and don't have a problem with that. Our problem has been electric outlets, but they aren't too bad.

I'm not sure that any of my room sizes are ideal, so I'll just echo what others have said about preferring square rooms. Most of the rooms in my house are long and narrow and therefore challenging to furnish. I dream of having square rooms. I think the proportion is more important than the square footage.

IMO on bedrooms: 10x is the minimum width and by 10 or by 12 is a small comfortable room for a kid (even with a full size or queen bed).

Master: 12 or 13 x 13 is also an excellent size--even for a king size bed (not a lot of room for extra furniture though, so make sure the closet is sufficient for clothing).

I have one bedroom that is 8.5 feet wide. And, it needs at least 1 foot more--1.5 feet (taking it to 10) would be excellent.

On the other rooms, I have less opinion. I think many bathrooms are fine at 5' wide. But, 7 is really small for the other dimension in that case.

Have fun!

This has been incredibly helpful to me ~ thanks so much everyone!!