Quick guide
How to use this calculator
- Enter amounts from the same property scenario and use consistent periods and units.
- Use visitor-entered rates and allowances from your own documents rather than assuming a local rule.
- Review the component results and the calculator-specific decision boundary before acting.
Calculation method
Calculation method
NPV = −net upfront cost + sum of each year's degraded net savings discounted to present value + discounted residual value.
Entered fixed decimals remain exact through rational arithmetic. Planar distance outputs that require square roots use bounded numerical evaluation. Values round only for display, and unsupported or undefined states return an explicit message.
Worked example
Worked example
A 12,000 project with 2,000 incentives and 1,400 first-year net savings is evaluated year by year rather than by simple payback alone.
NPV = −net upfront cost + sum of each year's degraded net savings discounted to present value + discounted residual value.
Supported inputs
Precision and limits
International scope
No currency, market price, interest rate, tax, tenancy rule, planning code, lender policy, or measurement definition is supplied automatically.
Scenario, not a decision
Results are arithmetic scenarios from visitor-entered values—not an appraisal, loan approval, legal interpretation, planning determination, forecast, or professional recommendation.
Precision and privacy
Inputs accept bounded plain decimals and remain in this browser. The engine prevents invalid denominators and misleading non-finite results.
Calculator-specific boundary
Savings, useful life, degradation and discount rate are visitor assumptions. Tax and financing are excluded unless reflected in entered cash flows.
Continue calculating