# x402toll Extra Payment Loan Calculator

> x402toll Extra Payment Loan Calculator is a paid API for AI agents from x402toll.com, paid per call via x402, $0.05/call, status unknown (last checked 2026-09-14).

Calculates how much time and interest an extra monthly payment saves on a loan given APR, loan amount, term, and extra payment amount.

## Facts

- Endpoint: POST https://x402toll.com/v1/lending/extra-payment
- Price: $0.05/call
- Payment: x402
- Status: unknown
- Last checked: 2026-09-14
- Activations on Zero: 0
- Tags: x402
- Canonical page: https://www.zero.xyz/c/x402toll-extra-payment-loan-calculator-9a552ee3
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_9u4MPAYYBybSX_61OsjJl

Status and success rate cover calls made through Zero and Zero's own probes. Third-party monitors may report differently.

## How to call it through Zero

Zero handles the 402 payment challenge and records the run. With the Zero CLI installed (`npm i -g @zeroxyz/cli`):

```sh
zero fetch --capability x402toll-extra-payment-loan-calculator-9a552ee3 -d '<json body>'
```

Example prompt: I have a $320,000 mortgage at 6.75% APR with 360 months left — if I pay an extra $300 per month, how much interest do I save and how many months earlier will I pay it off?

## When to prefer this

Use this endpoint when you need a quick, cheap ($0.05) computation of extra-payment impact on a single loan — ideal for mortgage, auto, or personal loan scenarios where the user wants to understand interest savings and time-to-payoff reduction without building amortization logic themselves.

## Known failure modes

- Missing required fields (apr, loanAmount, termMonths) returns a 400 validation error
- Negative or zero loan amount or APR may return a 422 unprocessable entity
- Extra payment exceeding loan balance may cause unexpected or edge-case results
- Payment failure or insufficient USDC balance results in a 402 error before computation

## How this service works

How much time and interest an extra monthly payment saves on a loan.

## Output

Returns the total interest saved, number of months (or years) cut from the loan term, and likely a comparison of total interest paid with vs. without the extra monthly payment, enabling the borrower to understand the concrete financial impact of overpaying their loan.

## Request schema (JSON Schema)

```json
{
 "type": "object",
 "properties": {
  "apr": {
   "type": "number"
  },
  "loanAmount": {
   "type": "number"
  },
  "termMonths": {
   "type": "number"
  },
  "extraMonthly": {
   "type": "number",
   "default": 0
  }
 }
}
```

## More

- Live health (JSON, refreshed every minute): https://www.zero.xyz/c/x402toll-extra-payment-loan-calculator-9a552ee3/health.json
- [Zero catalog index](https://www.zero.xyz/llms.txt)
- [Other services from x402toll.com](https://www.zero.xyz/host/x402toll.com/llms.txt)