# Loan Amortization Calculator

> Loan Amortization Calculator is a paid API for AI agents from finance.openverbs.com, paid per call via x402, $0.004/call, status unknown (last checked 2026-09-15).

Computes the level monthly payment, total paid, total interest, and optionally the full month-by-month amortization schedule for a fully-amortizing loan.

## Facts

- Endpoint: POST https://finance.openverbs.com/v1/loan
- Price: $0.004/call
- Payment: x402
- Status: unknown
- Last checked: 2026-09-15
- Activations on Zero: 0
- Tags: x402
- Canonical page: https://www.zero.xyz/c/loan-amortization-calculator-6446f79a
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_14qBpY3PUONoG8qQ9pBF3

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 loan-amortization-calculator-6446f79a -d '<json body>'
```

Example prompt: Can you calculate the monthly payment, total paid, and total interest for a $350,000 mortgage at 6.75% annual interest over 360 months, and also give me the full month-by-month amortization schedule?

## When to prefer this

Use this endpoint when you need to compute standard fully-amortizing loan metrics — monthly payment, total paid, and total interest — given a fixed principal, rate, and term. It correctly handles the 0% interest edge case and supports full amortization schedule output, making it ideal for mortgage, auto loan, personal loan, or any fixed-rate installment loan calculations. Prefer it over generic financial calculators when you need a structured, programmable result with optional per-period breakdown.

## Known failure modes

- Missing required fields (principal, annualRatePercent, termMonths) returns a validation error
- Principal of 0 or negative is rejected (exclusiveMinimum: 0)
- termMonths outside 1–1200 range returns a validation error
- annualRatePercent outside 0–1000 range returns a validation error
- principal exceeding 1,000,000,000,000,000 returns a validation error
- Payment failure or insufficient USDC balance (x402 protocol) blocks the request

## How this service works

Compute the level monthly payment, total paid and total interest of a fully-amortizing loan. Handles a 0% rate. Set schedule=true to also return the full month-by-month amortization table.

## Output

Returns the level monthly payment amount, total amount paid over the life of the loan, and total interest paid. If schedule=true is set, also returns a full month-by-month amortization table showing payment number, interest portion, principal portion, and remaining balance for each period.

## Request schema (JSON Schema)

```json
{
 "type": "object",
 "$schema": "https://json-schema.org/draft/2020-12/schema",
 "required": [
  "input"
 ],
 "properties": {
  "input": {
   "type": "object",
   "required": [
    "type",
    "method",
    "bodyType",
    "body"
   ],
   "properties": {
    "body": {
     "type": "object",
     "required": [
      "principal",
      "annualRatePercent",
      "termMonths"
     ],
     "properties": {
      "schedule": {
       "type": "boolean",
       "description": "Include the full amortization schedule. Default false."
      },
      "principal": {
       "type": "number",
       "maximum": 1000000000000000,
       "description": "Loan principal (amount borrowed).",
       "exclusiveMinimum": 0
      },
      "termMonths": {
       "type": "integer",
       "maximum": 1200,
       "minimum": 1,
       "description": "Loan term in months."
      },
      "annualRatePercent": {
       "type": "number",
       "maximum": 1000,
       "minimum": 0,
       "description": "Annual interest rate as a percentage, e.g. 5 for 5%."
      }
     },
     "additionalProperties": false
    },
    "type": {
     "type": "string",
     "const": "http"
    },
    "method": {
     "enum": [
      "POST"
     ],
     "type": "string"
    },
    "bodyType": {
     "enum": [
      "json",
      "form-data",
      "text"
     ],
     "type": "string"
    }
   },
   "additionalProperties": false
  }
 }
}
```

## More

- Live health (JSON, refreshed every minute): https://www.zero.xyz/c/loan-amortization-calculator-6446f79a/health.json
- [Zero catalog index](https://www.zero.xyz/llms.txt)
- [Other services from finance.openverbs.com](https://www.zero.xyz/host/finance.openverbs.com/llms.txt)