Garage Conversion Cost Calculator & Price Guide
Use our garage conversion cost calculator to estimate the cost for garage conversion projects across Australia, whether you want a simple extra room or a fully self-contained space. Typical garage conversion prices start from about $22,000 AUD for a bedroom or extra room and can reach about $75,000 AUD for a granny flat conversion on a single garage basis.
Estimate garage conversion cost
Build midpoints for one garage conversion in Australia. Rates cover a typical internal fitout on an existing slab. Council fees, new bathrooms, kitchens and structural steel are usually extra unless they are part of the granny-flat option.
Estimates are indicative only. For an accurate price, get free quotes from local tradies above.
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Garage Conversion Price Breakdown
Typical job based on 1 garage (Single garage). Prices are supply-and-install midpoints — actual quotes will vary.
| Type | Cost per garage (Single garage) | Typical 1 garage (Single garage) job |
|---|---|---|
| Bedroom / extra room | $22,000 | $22,000 |
| Living space / office / studio | $35,000 | $35,000 |
| Granny flat conversion | $75,000 | $75,000 |
What Affects Garage Conversion Cost?
- Type of garage conversion: The biggest driver of garage conversion cost is what you want the space to become. A bedroom or extra room starts at $22,000 AUD per single garage, a living space, office or studio is $35,000 AUD, and a self-contained granny flat conversion is $75,000 AUD.
- Garage size: A double garage costs more to convert than a single because the pricing uses a 1.5 multiplier. That means the garage conversion price increases significantly when more area needs to be lined, finished and fitted out.
- Slab and structural condition: If the existing slab is poor or extra structural work is needed, costs are multiplied by 1.3. This can apply even before higher-end finishes are considered, because the base structure needs to be made suitable first.
- Level of fitout and services: Projects with more power, lighting and a higher finish cost more than a basic room conversion. If you want to convert garage to granny flat, adding a bathroom and kitchenette is what pushes the price into the highest tier.
Garage Conversion Cost - Frequently Asked Questions
For a single garage, the midpoint cost depends on the end use. A bedroom or extra room is $22,000 AUD, a living space, office or studio is $35,000 AUD, and a granny flat conversion is $75,000 AUD. The displayed estimate range is usually shown at plus or minus 20% around those figures.
The garage conversion cost calculator uses the number of garages as the main input, with pricing based on a single garage rate. It then adjusts the garage conversion price by size and condition, using a 1.5 multiplier for a double garage and 1.3 for poor slab or extra structural work. Estimate ranges are displayed at ±20% around the midpoint, with a minimum job charge of $15,000 AUD.
To convert garage to bedroom or an extra room, the base price is $22,000 AUD for a single garage. This includes insulating, lining, flooring, and replacing the garage door with a wall or window, with no wet area included. For a double garage, apply the 1.5 size multiplier.
A living space, office or studio conversion starts at $35,000 AUD for a single garage. This is priced above a basic room conversion because it includes extra power, lighting and a higher level of finish. If the slab is poor or structural work is needed, the 1.3 multiplier applies.
If you want to convert garage to granny flat, the base cost is $75,000 AUD for a single garage. This covers a self-contained fitout with a bathroom and kitchenette on the existing garage slab. A double garage would be calculated using the 1.5 multiplier, and structural issues may increase costs further.
Yes, garage conversion contractors will generally price higher when the slab is in poor condition or extra structural work is required. In this pricing guide, that is reflected by a 1.3 multiplier on the selected conversion type. Even if the calculated figure is low, the minimum job charge is $15,000 AUD.
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