A purchase budget starts with income and obligations. A loan quote starts with principal and repayment rules. Keep those steps separate when exploring a property purchase.
Set a housing payment budget
The affordability worksheet subtracts other debts and property overhead from your entered income-based debt cap. The remainder is available for principal and interest. You choose the ratio; this is not lender approval. Include recurring taxes, insurance and fees as overhead.
Understand what remains unpaid
A fully amortizing loan aims to clear principal over its term. Interest-only payments leave principal untouched. A balloon loan leaves a separate final payoff. A smaller regular payment can therefore coexist with a large obligation later; compare both figures before drawing a conclusion.
Inspect cash needs and the final balance
Download the balloon schedule and check its remaining principal. Cents rounding can move the final balloon slightly from the theoretical target. Down payments, closing costs, repairs and reserves affect cash needed beyond the modeled purchase price. Underwriting and local disclosures remain separate checks.
Worked example
Scroll the table horizontally on small screens to see every column.
| Principal | Rate | Months | Regular payment | Balloon |
|---|---|---|---|---|
| 1,200 | 0% | 12 | 50 | 600 |
Twelve payments of 50 repay only 600. The other 600 is still due after the regular payments.
Sources and checks
- https://openstax.org/books/principles-finance-2e/pages/8-3-loan-amortization ↗
- https://www.consumerfinance.gov/owning-a-home/compare/compare-loan-estimates/ ↗
Examples are illustrative and can be checked with the linked tools. Read each tool’s assumptions before applying its result. How we verify methods.