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Finance & LoansGenerated accuracy model review: 2026-05-06
Rental Property accuracy and testing
This page documents how Calwarden builds trust for this calculator: source notes, regression-style default tests, limitations, assumptions, unit handling, rounding, and visible change history.
Formula source
- 1. **Cash Flow** = Rent - (Mortgage + Expenses). 2. **NOI (Net Operating Income)** = (Rent - Operating Expenses) * 12. 3. **Cap Rate** = NOI / Purchase Price. 4. **Cash on Cash Return** = Annual Cash Flow / Total Cash Invested.
Test cases
Default input regression check
Generated from the checked-in default inputs and calculate function.
Inputs
- Purchase Price: $250,000
- Monthly Rent: $2,000
- Monthly Mortgage: $1,200
- Operating Expenses: 400 $/mo
- Cash Invested: $55,000
Expected outputs
- Monthly Cash Flow: $400.00
- Cash on Cash ROI: 8.73%
- Cap Rate: 7.68%
Known limitations
- Does not calculate internal rate of return (IRR) based on future appreciation or tax benefits (depreciation).
Assumptions
- Inputs are interpreted exactly as entered in the calculator form.
- The calculation runs locally in the browser using the current checked-in calculator definition.
Unit handling
- Purchase Price accepts values in $.
- Monthly Rent accepts values in $.
- Monthly Mortgage accepts values in $.
- Operating Expenses accepts values in $/mo.
- Cash Invested accepts values in $.
- Monthly Cash Flow is displayed as currency.
- Cash on Cash ROI is displayed as a percentage.
- Cap Rate is displayed as a percentage.
Rounding rules
- Number displays use up to 2 decimal places in the calculator UI.
- Currency outputs are displayed with standard US dollar formatting.
- Percent outputs are displayed with two decimal places.
Version history
1.0.0 - 2026-05-06
Generated accuracy and testing page from the current rental-property-calculator calculator definition.
Change log
2026-05-06
Published default regression test documentation and metadata fallbacks for Rental Property.
Calculator transparency
Accuracy pages are generated from checked-in calculator definitions and can be upgraded with curated review metadata over time.