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
Loss or gain to lease = market rent − contractual rent; portfolio amount sums area or unit basis × the per-basis difference.
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
Contract rent of 28 and market rent of 30 across 10,000 area units creates 20,000 annual loss to lease.
Loss or gain to lease = market rent − contractual rent; portfolio amount sums area or unit basis × the per-basis difference.
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
Market rent is visitor-entered and requires valuation evidence. Positive mark-to-market is not guaranteed realizable income.
Continue calculating