Construction Cost Calculator

1. Base cost. Floor area (m²) multiplied by the rate per square metre for your city, project type and finish level. Residential rates are city-specific. Commercial rates are set by building type and finish level.
2. Waste allowance. 5% added to the base cost for cutting, breakage and spillage across all trades.
3. Contingency. Your choice of 3% for a well-defined scope, 5% for a standard project, or 10% for complex work and renovations, applied to the subtotal.
4. Builder overhead (optional). 10% for site establishment, supervision, temporary services and insurance.
5. Profit margin (optional). 5%, the industry-average figure, applied after overhead.

The result shows each line and an effective rate per square metre, so you can compare it with a quote line by line.

Assumptions and limits

• Rates assume a new build on a flat, serviced block with normal site access. Sloping sites, rock, reactive soil and tight access all add cost.
• Land, demolition, professional fees, council and authority charges, and finance costs are excluded.
• Three finish levels only. A genuinely bespoke or architect-led home can exceed the high-spec rate.
• Regional and remote locations are not modelled. Expect higher rates outside the five capital cities, driven by transport and labour availability.
• Figures are indicative and for budgeting. They are not a quote, a valuation or advice.

Regional variance

The same house does not cost the same in every capital. In the calculator's base data a basic residential build in Sydney sits roughly 20% above Perth, with Melbourne close behind Sydney and Brisbane and Adelaide in between. Brisbane is carrying the highest current cost escalation of the five cities, so Queensland budgets need more headroom than the base rate alone suggests. Commercial work moves with building type more than city: healthcare fit-outs sit well above industrial sheds at every finish level.