# Build a loan amortization schedule from an AI agent

You need the payment and the interest and principal of each period for a level-payment loan, rounded to the cent.

**Use `loan-amortization-schedule@1.0.0`.** It is free and needs no key or sign-up. Cent-exact level-payment loan schedule with per-period rounding, extra payments, dates and a row window.

## Why call a tool for this

Each row depends on the rounded balance of the row before it, so one rounding slip carries through to the end. The tool returns the rows and the totals in one response.

## Call it over HTTP

```sh
curl -X POST https://computefirst.net/v1/tools/loan-amortization-schedule/versions/1.0.0/execute \
  -H "Content-Type: application/json" \
  -d '{"principal":"8000","annual_rate":"0.1","periods":36,"from_period":1,"to_period":1}'
```

Response:

```json
{
  "result": {
    "payment": "258.14",
    "periodic_rate": "0.0083333333",
    "periods_scheduled": 36,
    "periods_actual": 36,
    "payoff_date": null,
    "rows": [
      {
        "period": 1,
        "date": null,
        "payment": "258.14",
        "interest": "66.67",
        "principal": "191.47",
        "extra": "0.00",
        "balance": "7808.53"
      }
    ],
    "totals": {
      "total_paid": "9292.94",
      "total_interest": "1292.94",
      "total_principal": "8000.00",
      "total_extra": "0.00"
    },
    "window_totals": {
      "total_paid": "258.14",
      "total_interest": "66.67",
      "total_principal": "191.47",
      "total_extra": "0.00"
    },
    "baseline": null,
    "savings": null
  }
}
```

## Call it over MCP

Connect `https://computefirst.net/mcp` ([setup](/docs#connect)), then call `execute` with:

```json
{
  "id": "loan-amortization-schedule",
  "version": "1.0.0",
  "input": {
    "principal": "8000",
    "annual_rate": "0.1",
    "periods": 36,
    "from_period": 1,
    "to_period": 1
  }
}
```

## Check the result

Pass annual_rate as a fraction, so 0.06 for 6 percent. Check that the rate, the number of periods and the optional extra payments match the loan terms. This is arithmetic on the terms you give it, not financial advice.

Full contract, limits and unsupported cases: [Loan amortization schedule](/tools/loan-amortization-schedule).

## Related tools

- [Loan apr compute](/tools/loan-apr-compute)
- [Tvm solve](/tools/tvm-solve)