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Finance & LoansGenerated accuracy model review: 2026-05-06
Rent Calculator 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. **30% Rule**: Housing costs should not exceed 30% of your gross monthly income. We adjust this downward if you have high debts. 2. **40x Rule**: Annual Income / 40. This is common in cities like NYC (e.g., earn $100k to rent $2,500).
Test cases
Default input regression check
Generated from the checked-in default inputs and calculate function.
Inputs
- Annual Gross Income: $50,000
- Monthly Debts: $0
Expected outputs
- Max Recommended Rent: $1,250.00
- 40x Rule Limit: $1,250.00
Known limitations
- Does not account for upfront costs like Security Deposit, Broker Fee, or First/Last month rent.
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
- Annual Gross Income accepts values in $.
- Monthly Debts accepts values in $.
- Max Recommended Rent is displayed as currency.
- 40x Rule Limit is displayed as currency.
Rounding rules
- Number displays use up to 2 decimal places in the calculator UI.
- Currency outputs are displayed with standard US dollar formatting.
Version history
1.0.0 - 2026-05-06
Generated accuracy and testing page from the current rent-affordability-calculator calculator definition.
Change log
2026-05-06
Published default regression test documentation and metadata fallbacks for Rent Calculator.
Calculator transparency
Accuracy pages are generated from checked-in calculator definitions and can be upgraded with curated review metadata over time.