How are house sizes calculated and what's an average/large house size?

Hi guys,

We're currently in the throws of designing a single story house with an architect and I'm having some trouble getting a feel for what an average and large house is and how house sizes (area) are calculated. Are house sizes, when advertised via real estate agents etc., stated as the total living space under roof, not including the garage, pool, outdoor entertainment areas etc.?

A bit of background: We moved from Sydney to the Sunshine Coast last year and we've bought a large, beautiful block of land in the rural part of the Sunshine Coast. We previously owned and lived in a large 3 bedroom apartment in Manly which was around 240sqm with a 54sqm balcony.

We're in early concept stages and the total size of the main house is 275sqm. The total build area including living space, guest house (90sqm), pool, outdoor entertainment, garage, master bedroom balcony etc. is 575sqm. I'm mostly concerned about the size of the main house living area and my concern is that this feels like it's going to be too small/pokey especially coming from a large apartment.

Am I being unrealistic? I'm hoping there's some builders or others who've recently built on here who might be able to help provide some guidance of the area of an average sized home (just living space) and a large home and are modern homes in Australia advertised per their actual living area?


  • +2 votes

    Can always go to home open or a friend's house to see first hand how big it is.

  • +3 votes

    Yeah. Display homes, go check out a few to grasp an idea of the sizes.


      Thanks mate. Do you know whether the areas advertised on display homes includes garage, pool, outdoor area etc?

      • +1 vote

        All will have garages and outdoor areas, some may have pools.

        Majority of these houses are the most common type with all the fancy upgrades added in.


          Yeh, I think I've figured it out. 'Home sizes' advertised in Australia include all roof covered areas including garage, covered outdoor areas and pools I think. I'll go and visit a few over the weekend to get a feel for their sizes.

          • +1 vote

            @gyrex: Yea, it has the breakdown of specific areas in the bottom left in the imgur link.


    To me

    Small is 100sqm for house with two bedroom and 20sqm for every room above two.

    Average is 150sqm for house with two bedroom and 30sqm for everyroom above two.

    Large is 200sqm for a house with two bedroom and 50sqm for everyroom above two.

    *excludes garages, patios and stairwells

    **may require more space if shape is excessively long or unique.

    • +1 vote

      Yeh that makes sense and that methodology is really logical - thanks mate!

  • +2 votes

    From a mindset point of view, do you need this much space or do you want this much space?

    • -1 vote

      We're really dictated by the land we bought. The land is massive - 1.2ha with a 75m frontage on an elevated block on top of a mountain with uninterrupted views stretching eastward over the lush hinterland to the ocean. Putting a small house on the block wouldn't do it justice and we bought the block for the view so we're trying to maximise it as much as possible. We're attempting to build a house that feels spacious, uncluttered and open to the environment.

      I'm probably overthinking it since it's the first house I've ever built. I'm just worried that if we skimp on space we'll regret it post build. I probably need to relax a little :)

      • +1 vote

        1.2ha with a 75m frontage on an elevated block on top of a mountain with uninterrupted views stretching eastward over the lush hinterland to the ocean.

        Is your job writing real estate listings? Sounds dreamy and expensive.

        • +1 vote

          haha no, I just enjoy writing :) It sure is super dreamy and my wife and I are very lucky. To be honest, I got a great price on my apartment and I'm effectively swapping an overpriced apartment in Sydney for land and some money left over which will partially pay for the house build in a region which provides much more value for money. This project is definitely costing me more than I initially wanted to spend but I feel it's a good 'life investment'. I'm naturally a tight-arse hence being on here but there's some things in life which are worth spending money on.

          • +1 vote

            @gyrex: I'm on 20ha. House is just under 450sqm including 2.5 car garage and verandahs. Heaps of room. I don't like big houses but I like oversized rooms with high ceilings.

            My shed is 400sqm. That's my favourite part.


              @MS Paint: 20ha??? Bloody hell, that's frikken enormous! It's hard to try and imagine that kind of size… 200,000sqm. If it were a perfect square your block would measure 450m x 450m - nuts! Where's your block? Yeh, there's some massive man sheds up here too, I've had to keep mine within reason haha! Maybe later I can expand it ;) Since I've moved from Sydney, I'm absolutely loving the serenity and space afforded up here - you must feel like you're living on your own planet on your block :)

              I hear what you're saying about big houses - we're definitely not trying to make it big but you've hit the nail on the head with the oversized rooms and high ceilings, that's exactly what we're trying to achieve. Flat roof, high ceilings with shitloads of floor to ceiling glass.

              • +1 vote

                @gyrex: Block is 500x400m. Nearest neighbour 1km away. Regional area with 30k residents on the banks of the 16th longest river in the world. I wouldn't have it any other way.


                  @MS Paint: Sounds magnificent! You're living the Aussie dream in my book. Is the Murray flowing where you are? I hope you got lots of rain recently mate.

                  • +1 vote

                    @gyrex: Murray is flowing nicely. Pretty well managed in my area thanks to weirs. I actually prefer no rain over the summer. All it does is encourage weeds. 😁


                      @MS Paint: How are the mosquitos? I'm on the parramatta river and they attack on sight.


                        @elgrande: No still water in my area for mozzies. But the flies make up for that. Horse + Cow Shite = flies


                @gyrex: 1ha is 2 football fields side by side.

                Using that as a base helps ‘imagine’ 20ha.


        My block has a similar view but much larger.

        Do not overcapitalize on the view. The previous owner obviously had the brief of "ALL THE VIEW!".

        I ended up planting a few hundred trees to frame the view and accents the land and sea in front.

        Also, if you're thinking of all glass towards the sea and no trees, thats a lot of sea breeze to the yard between you and the sea. You'll be limited to very coastal plants and practically no flowers as the wind will drop the flowers before bloom.

        Final consideration is room layout. If you overcapitalize on the view, the location of your cabinetry throughout the house will suffer.

        Adding a second floor instead of trying to use up as much land will also make a difference. The view from 3m up is significantly different than ground floor view. You practically do not see any dirt and the features of the trees from up there is entirely different.

        If you still feel the land feels too sparse, put up a workshop a solid 15-20m from the house and a few smaller storage sheds/machine sheds. It will give it the visual appeal of a village vs a single house on a block. To maintain your block, you're going to need machines so factor in appropriate storage.

        Ps. Just saw your comments below, you are in QLD. The wind isn't nearly as strong as where I am so you could probably have a "cleaner" view without copping gale force winds every second day.

  • +4 votes

    Damn son, you must be rolling in that $$$.

    575 sqm house is excessively large in most people's understanding. I'd say you'd probably be in the top 5% of houses in that size.

    Even a 240 sqm apartment is huge for most apartments.


    The question is what do you need? not what is considered big and small. I am building a 190m2 house in Sydney, we look at a display, it's not huge BUT the designs so well thought out and placed we don't need any bigger.

  • +1 vote

    Here is a comparison for you. 520 sqm is 56 squares (and yes we need a cleaner as it is just too big for us to do as we both work adn that doesn't include our pool area) so your 275 sqm is roughly 29/30 squares of living space. Take a drive to a housing display and look at houses in this size range to see what you can get.

    I presume you're looking at single storey? The first house I built was a single storey 24 square. All fine and practical but the rooms were just a fraction too small. For example the master bedroom could take a queen bed but a king bed would have crowded it. We loved the house but once our son came along we just outgrew it. If your living area is 275, guest house 90 and including the pool and other areas in your calculations, I'm left wondering if you're making the best use of the space available. What are the notional bedroom sizes? One living area or two? Are you going 3, 4 or 5 bedrooms? If you're already feeling that it is hokey pokey, then that's a sign that the design needs a lot more work.

    Don't feel pressured into rushing into the thought of "I've got to build this asap". When we bought our current block of land, it took almost 2 years before we settled on a design with an architect and builder that we that we were comfortable with and it was worth the wait.


    It’s not all about the overall size of the house. It is about the design and space. You could have a really large m2 house poorly designed that feels cramped and viceversa.

    You probably need to check the size of individual rooms to determine if they are big enough.

    I’d like to see 4x4 for a large bedroom 4x5 for a large master. Living space depends on the flow.

    Don’t forget that often display homes will have smaller furniture to make the space feel larger.