28/36 Rule Debt Calculator
Calculate your maximum affordable mortgage payment using the traditional 28/36 underwriting rule. Model front-end housing and back-end debt caps.
What is the 28/36 Rule Debt Calculator?
The 28/36 qualifying rule calculates standard mortgage underwriting debt-to-income limits to determine prudent residential borrowing capacity for prospective home buyers. It limits monthly housing expenses to twenty-eight percent and total recurring debt obligations to thirty-six percent of gross monthly household income. This empowers prospective mortgage applicants to evaluate loan eligibility, avoid loan application rejection, and maintain sustainable long-term household debt levels.
Financial Calculation Inputs
- Supported Inputs: Principal balances, interest rates, compounding schedules, and tenures.
- Precision Model: High-precision IEEE-754 floating-point arithmetic with decimal rounding.
- Data Privacy: Zero cloud logs. Figures are calculated locally in your browser memory.
Output & Schedule Breakdown
- Visual Analytics: Month-by-month schedules, dynamic charts, and cash flow summaries.
- Currency Support: Multi-currency symbol formatting (USD, EUR, GBP, INR, JPY, CAD, AUD).
- Access Guarantee: 100% unlocked with zero limits, subscriptions, or forced account creation.
How to Use the 28/36 Rule Debt Calculator
Follow these 3 simple steps for instant, accurate calculations.
1. Enter Gross Monthly Income
Input your total pre-tax household monthly earnings.
2. Input Recurring Non-Housing Debts
Add auto loans, student loans, minimum credit card payments, and child support.
3. Set Down Payment & Interest Rate
Specify available cash down payment and current prevailing mortgage interest rates.
Financial Privacy & Architecture Comparison
Why client-side financial calculations protect your privacy better than cloud services.
| Evaluation Criteria | ToolboxDock (Client-Side) | Traditional Online Calculators |
|---|---|---|
| Financial Data Privacy | 100% In-Memory Client Execution (Zero Server Transit) | Logged on remote servers and ad networks |
| Calculation Latency | Instant real-time update on keystroke | Full page reloads or API round-trips |
| Offline Usability | Works offline once cached in browser | Fails without active server connection |
| Cost & Paywalls | 100% free with unlimited calculations | Usage caps or financial product paywalls |
The 28/36 Underwriting DTI Formula
Caps monthly housing costs (principal, interest, taxes, insurance) at 28% of gross income and total debt obligations at 36% of gross income, taking the lower of the two limits.
Frequently Asked Questions
Common questions about using our free 28/36 Rule Debt Calculator.