# Ledgerly Debt Payoff Planner

> Avalanche vs snowball: your debt-free date, total interest and a month-by-month plan. Plans paying off several credit cards and loans: the avalanche (highest interest first), snowball (smallest balance first) or your own order with an extra monthly payment, compared with paying only the minimums. Shows the debt-free month, total interest, when each debt is gone, a month-by-month table and the minimum-payment trap of every card with a percentage minimum. Part of Ledgerly’s Debt & Growth.

Part of usefulweb.app (https://usefulweb.app/). Part of [Ledgerly](https://ledgerly.usefulweb.app/) (ownerApp: ledgerly). Results are deterministic calculations from the inputs and the listed assumptions; the API returns exactly what the web page shows.

## Use it
- Human interface: https://ledgerlydebtpayoff.usefulweb.app/ (interactive tool at https://ledgerlydebtpayoff.usefulweb.app/tool)
- JSON API: POST https://ledgerlydebtpayoff.usefulweb.app/api/v1/calculate with a JSON object of inputs (schema: https://ledgerlydebtpayoff.usefulweb.app/api/v1/tool)
- OpenAPI: https://ledgerlydebtpayoff.usefulweb.app/openapi.json
- MCP (Streamable HTTP): https://ledgerlydebtpayoff.usefulweb.app/mcp - tool `ledgerly_debt_payoff`

## Inputs
- currency (text): Currency - ISO code used for the labels, e.g. EUR, USD, GBP.
- debts (table, required): Debts - One row per credit card or loan. Cards often have a minimum of a percentage of the balance (e.g. 2 %) with a fixed floor (e.g. 25): enter both; for a fixed payment leave the percentage at 0.
- strategy (select): Payoff order
- extraPerMonth (number): Extra payment per month on top of the minimums
- minimumRule (select): Percentage minimums are - Only used for debts with a percentage minimum (credit cards). The fixed amount is the floor.
- startMonth (text): First payment month (YYYY-MM, optional) - Gives the debt-free date as a month; leave empty to count months only.

## Method
- Each month one twelfth of the APR is added to every balance as interest (rounded to the cent, as in the Loan Amortization Calculator’s schedule).
- The monthly amount is fixed: the first month’s minimums plus your extra payment. Every debt gets its minimum; the rest goes to the first open debt in the payoff order. When a debt is paid off, its minimum rolls over to the next one.
- Avalanche orders by interest rate (highest first), snowball by balance (smallest first), “your order” keeps the list order; ties keep the list order.
- Percentage minimums are the percentage of the balance (or the month’s interest plus the percentage), never below the fixed amount and at least 1 unit of the currency. “Minimum payments only” pays each debt just its own minimum, so card payments shrink as the balance falls — the minimum-payment trap.

## Limits
- A plan, not financial advice: lenders calculate interest and minimums in different ways, and rates can change. Check your statements and talk to a free debt advice service if payments are hard to make.