construction cost estimator

Try our improved construction cost estimator...

The calculator is on our affiliated web site. The URL is:
http://www.homedesigndirectory.com.au/calculators/ConstructionCostEstimator.shtml

caveat lector! (reader beware!)

This construction cost estimator is only that: an estimator. Because there are so many variables that affect cost for accuracy you will require detailed plans and the services of a quantity surveyor or licensed builder. But when making "back-of-an-envelope" preliminary estimates the method used below, or some variation thereof, is what is used by building professionals. Also note that the costs generated by this calculator apply best to the Central Coast of NSW, Australia, but the logic used should be reasonably universal.

question 1: is the project a renovation or new home design?

new home design     renovation

NOTE:  On a per-square-metre basis renovations are invariably more expensive than building a new house. Thus it is prudent to explore two cost saving options: (1) knock-down and rebuild, or (2) leave the current building essentially untouched and attach a new building using a walkway or some other mechanism.

question 2: what is the size of the renovation or new home design?

Select from small, medium or large to set defaults for the areas specified in the table below. Then change the default values to values appropriate for your renovation or new home design.

If an area/space does not apply to your renovation or new design you must put in the value "0" (i.e., zero).

Note: All areas must be specified in square-metres and the total calculated indoor area will include 10% for circulation; i.e., hallways, entrances, stairways, etc.

select to change defaults: small    medium    large
kitchen master bedroom
lounge room/space bedroom 2
rumpus room/space bedroom 3
study bedroom 4
laundry main bathroom
verandah's & decks garage
circulationadd 10% other areas
 total indoor living space
 total area (includes all spaces)


question 3: what are the building site conditions?

excellent (e.g., flat/level block)
good (e.g., slightly sloping block)
difficult (e.g., steep block, land that requires clearing, etc.)

NOTE:  Flat/level blocks are of course the easiest & cheapest blocks to build on unless they have water drainage or other complications. If that is the case with your block, you should select "difficult".

question 4: what quality of finishes will you use?

basic
standard
luxury

NOTE:  Quality of finishes refers to PC items like toilets, tiles, bathtubs, sinks and taps as well as doors, door handles etc.

cost estimate:



$ indoor areas per square metre
$ garage per square metre
$ verandahs/decks per square metre
$ total cost


Note 1: The assumptions used by this construction cost estimator are as follows:
  • A new home design on an excellent site using basic finishes will cost $1500/square-metre.
  • A new home design on an excellent site using standard finishes will cost $1700/square-metre.
  • A new home design on an excellent site using luxury finishes will cost at least $1900/square-metre.
  • If the site is "good", but not excellent, add 7% to the cost.
  • If the site is "difficult", add at least 20% to the cost.
  • Renovations often cost twice as much, per square metre, as new home construction.
  • Reasonably well built garages typically cost $1200/square-metre.
  • Decks and/or verandahs typically cost $900/square-metre.
Note 2: The costs generated by this calculator apply best to the Central Coast of NSW, Australia, but the logic used should be reasonably universal.