Granny Flat Planning Tools
Free calculators and checkers for Australian homeowners — approval pathways, size caps, build types and metering costs.
Full build budget
Four-phase estimate for site, build and finishes across all states.
Open calculatorApproval pathway wizard
CDC vs DA likelihood by state, lot size and proposed floor area.
Start wizardSize eligibility checker
Compare your proposed sqm to common state secondary-dwelling caps.
Check sizeBuild type comparator
Kit vs prefab vs custom — timeline, cost band and best fit.
Compare pathsMetering estimator
Separate meter and sub-board connection cost bands for rentals.
Estimate costsPlanning tools FAQs
Are these granny flat tools free?
Yes. Every tool on this hub is free to use in your browser with no sign-up. Results are indicative only — confirm with your council, certifier or licensed trades before you lodge or sign contracts.
Which tool should I use first?
Start with the approval pathway wizard if you are unsure whether CDC or a full DA applies. Then check size caps with the size eligibility checker and budget with the cost calculator.
Do the tools replace professional advice?
No. They summarise common Australian rules and cost bands for planning. A private certifier, town planner or builder still needs to verify your specific lot, overlays and contract scope.
Related guides
Tools give you a starting point. These pages go deeper on rules, costs and design.
