# Amortization Schedule

Builds a full period-by-period amortization schedule — principal, interest, PMI, extra-principal, running balance — for monthly or daily-accrual loans, with the last payment corrected to actually zero the balance instead of drifting by rounding error. Handles biweekly acceleration, one-off or recurring extra principal, and PMI cancellation at 80/78% LTV.

**Not for:** This is not a lender's payoff quote, a TILA/RESPA disclosure, or tax or accounting advice, and it does not model rate changes on an ARM, escrow shortages, late fees, or a servicer's specific PMI-cancellation policy (which by law may use the original amortization schedule rather than your actual balance). Treat its numbers as a planning estimate to check your statement against, not a substitute for it.

## Surfaces

- HTML: `https://amortize.gumballtools.com`
- Markdown: same URLs with `Accept: text/markdown` or `?format=md`
- JSON API: `https://amortize.gumballtools.com/api/v1/run` (POST a JSON body shaped like the engine input, or GET with query params)
- OpenAPI: `https://amortize.gumballtools.com/.well-known/openapi.json`
- MCP: `https://amortize.gumballtools.com/api/mcp`