Initial estimates for new homes,
renovations & additions
Tap arrows to instantly change values
Choose options to suit your job
How to use this calculator
To use the calculator page simply click on the up or down arrows (like the ones shown on the right) to increase the number of rooms or the room area. The estimated cost will increase or decrease automatically after each click.
Indoor circulation refers to hallways, stairs & entrances. For a basic house use 10%. If you want the house to feel spacious use 20% - 25%.
If rooms are different sizes use an average size or upgrade to the professional version when it become available.
Use the set-up page (accessible from the home page) to change the underlying values used to estimate the cost of construction.
Rules built into by this construction cost calculator are as follows:
(1) If the job is a renovation or addition double the base rate.
(2) If the site is "fair", and the project type is 'new building', add 7% to the base rate.
(3) If the site is "difficult", and the project type is 'new building', add 20% to the base rate.
(4) If the quality of finishes is 'standard', add $300 to the per-square-metre cost.
(5) If the quality of finishes is 'high', add $600 to the per-square-metre cost.
These rules are not applied if you set your own per-square-metre costs.
How to set-up this calculator
Step 1: Select a project type. On a per-square-metre basis renovations & additions are usually more expensive than building a new house. This calculator assumes they are twice as expensive, but this is not necessarily the case; we recommend you consult a licensed builder or architect. It is also prudent to explore two cost saving options: (1) knock-down & rebuild, or (2) leave the current building essentially untouched and attach a new building using a walkway or some other mechanism.
Step 2: Select site conditions. Flat/level blocks are of course the easiest & cheapest blocks to build on and if this is the case with your property select "good", unless the block has water drainage or other complications, in which case select "difficult". Steeply sloped properties should also be marked as difficult. Use "fair" for slightly sloping properties. Note that if you selected "renovations & additions" whatever you select here will not change the per-square-metre cost; it is assumed this is already factored-in to the calculator by doubling the base rate for renovations & additions.
Step 3: Select quality of finishes. Quality of finishes refers to PC items like toilets, tiles, bathtubs, sinks and taps as well as doors, door handles etc. By selecting "basic" you are implying that you will be buying PC items where cost is of higher concern than quality or style. Selecting "standard" implies that quality is as important as cost, but style is less important than either. If you select "high" you are implying that style and quality are more important than cost.
Optional: Set your own per-square-meter values. Select realistic values for your area. The best way to do this is to call a few builders in your area and ask. Values you enter will override the values set in steps 1 to 3.
Rules built into by this construction cost calculator are as follows:
(1) If the job is a renovation or addition double the base rate.
(2) If the site is "fair", and the project type is 'new building', add 7% to the base rate.
(3) If the site is "difficult", and the project type is 'new building', add 20% to the base rate.
(4) If the quality of finishes is 'standard', add $300 to the per-square-metre cost.
(5) If the quality of finishes is 'high', add $600 to the per-square-metre cost.
These rules are not applied if you set your own per-square-metre costs.
Getting started
Please note: This construction cost calculator only gives an estimate of building costs. It is only suitable for use before any detailed plans are made.
Step 1: Use the setup page to setup default values and parameters. Click the button below for help with setup.
Step 2: Use the calculator page. Click the button below to go to the calculator help page.
Learn more about building a house
Construction process
Miscellaneous