Calculation method
GRV Calculator
Number of dwellings × sale price by dwelling type. Keep the evidence date, source, range and confidence beside each sale value.
Open the full feasibility model →Transparent development maths
Calculators
Understand how each assumption changes an Auckland residential development result. The main feasibility model combines all seven methods; the cards below explain each control before you use it.
Free public resource · Last reviewed 8 August 2026
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Development feasibility
Feasibility Calculator
Model residual land value, margin, costs and sensitivity.
Open resourceFinance and sensitivity
GST / Tax Assumption Checker
Open BuildPath NZ guidance and practical controls for gst / tax assumption checker.
Open resourceFinance and sensitivity
Sensitivity Calculator
Open BuildPath NZ guidance and practical controls for sensitivity calculator.
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7 resultsDevelopment feasibility
Feasibility Calculator
Model residual land value, margin, costs and sensitivity.
GRV Calculator
Open BuildPath NZ guidance and practical controls for grv calculator.
Development Margin Calculator
Open BuildPath NZ guidance and practical controls for development margin calculator.
Residual Land Value Calculator
Open BuildPath NZ guidance and practical controls for residual land value calculator.
Finance and sensitivity
GST / Tax Assumption Checker
Open BuildPath NZ guidance and practical controls for gst / tax assumption checker.
Interest Calculator
Open BuildPath NZ guidance and practical controls for interest calculator.
Sensitivity Calculator
Open BuildPath NZ guidance and practical controls for sensitivity calculator.
Calculation method
Development Margin Calculator
Compare final profit with total cost and net revenue. Review both margin on cost and margin on revenue.
Open the full feasibility model →Calculation method
Residual Land Value Calculator
Work backwards from net sales, non-land cost and the required return to test the maximum supported land price.
Open the full feasibility model →Calculation method
GST / Tax Assumption Checker
Record whether each input is GST-inclusive, GST-exclusive, zero-rated, exempt or unverified. Confirm the treatment with a New Zealand tax adviser.
Open the full feasibility model →Calculation method
Interest Calculator
Test the amount borrowed, annual rate and months outstanding separately for land and the main project facility.
Open the full feasibility model →Calculation method
Sensitivity Calculator
Stress sale price, yield, land, civil, construction, programme, interest, selling cost, tax and contingency assumptions.
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