Useful numbers. Clear assumptions.
Practical tools for Australian projects and trade businesses.
What these tools do
66 calculators cover quantities, geometry, budgets, water, energy and business planning. They do not provide engineering designs or certified quantities.
Starting values
Field values and worked examples illustrate arithmetic. Verify values against your project. Supplier coverage, material density, bag yield and tariffs vary. Costs must have consistent inclusions and GST treatment.
Privacy
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Australian defaults
GST uses 10% for fully taxable supplies. Employee super defaults to 12%; eligibility and limits require separate assessment. Sources reviewed 7 October 2026.
ATO GST guidance · ATO super guidance
Use the right product information
Confirm coverage, dimensions and performance with your supplier. Links to specialist resources do not mean those publishers endorse these calculators.
Your next step
Use your results to prepare a project brief and discuss quantities, scope and pricing with a suitable trade professional. Calculator use does not post a job or contact a tradie.