# Finance Calculators – Loan Payment & Amortization

> Finance Calculators – Loan Payment & Amortization is a paid API for AI agents from finance-calculators.x402tookit.com, paid per call via x402, $0.02/call, status unknown (last checked 2026-10-31).

Calculates monthly (or custom-frequency) loan payment, total interest, total paid, and an amortization preview given principal, annual rate, and term.

## Facts

- Endpoint: GET https://finance-calculators.x402tookit.com/loan-payment?utm_source=zero.xyz
- Price: $0.02/call
- Payment: x402
- Status: unknown
- Last checked: 2026-10-31
- Activations on Zero: 0
- Tags: x402
- Canonical page: https://www.zero.xyz/c/finance-calculators-loan-payment-amortization-87ec4b25
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_8zxpMg7O2yn0mynBB2VmX

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 finance-calculators-loan-payment-amortization-87ec4b25
```

Example prompt: What would my monthly payment be on a $250,000 loan at 6.5% annual interest over 30 years, and how much total interest would I end up paying?

## When to prefer this

Choose this endpoint when you need a quick, accurate loan payment and total-interest estimate with an amortization preview — especially when the user supplies principal, rate, and term and wants both the periodic payment and the full interest cost. It supports non-monthly payment frequencies (bi-weekly, etc.) which many simple calculators omit. Prefer this over general financial APIs when you specifically need amortization breakdown data alongside the payment figure.

## Known failure modes

- Missing required parameters (principal, annual_rate_pct, years) returns an error
- Non-positive or zero principal or rate may yield invalid results
- Extremely short terms or very high rates may produce edge-case outputs
- Network or payment (x402) authentication failure results in no response
- payments_per_year of 0 or negative would cause division errors

## How this service works

Loan payment, total interest and amortization preview from principal, annual rate and term, monthly or other frequency.

## Output

Returns a structured object with: the periodic payment amount, total number of payments, total amount paid, total interest paid, interest as a percentage of principal, a human-readable summary, a disclaimer, and an array showing the first and last amortization entries (with balance, payment, interest, and principal components for each).

## 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"
   ],
   "properties": {
    "type": {
     "type": "string",
     "const": "http"
    },
    "method": {
     "enum": [
      "GET"
     ],
     "type": "string"
    },
    "queryParams": {
     "type": "object",
     "required": [
      "principal",
      "annual_rate_pct",
      "years"
     ],
     "properties": {
      "years": {
       "type": "number",
       "description": "Term in years"
      },
      "principal": {
       "type": "number",
       "description": "Amount borrowed"
      },
      "annual_rate_pct": {
       "type": "number",
       "description": "Annual interest rate in percent, e.g. 6.5"
      },
      "payments_per_year": {
       "type": "integer",
       "description": "Default 12"
      }
     }
    }
   },
   "additionalProperties": false
  },
  "output": {
   "type": "object",
   "required": [
    "type"
   ],
   "properties": {
    "type": {
     "type": "string"
    },
    "example": {
     "type": "object",
     "properties": {
      "asOf": {
       "type": [
        "null",
        "string"
       ]
      },
      "source": {
       "type": [
        "null",
        "string"
       ]
      },
      "payment": {
       "type": [
        "null",
        "number"
       ]
      },
      "reasons": {
       "type": [
        "array",
        "null"
       ],
       "items": {
        "type": "string"
       }
      },
      "summary": {
       "type": [
        "null",
        "string"
       ]
      },
      "verdict": {
       "type": [
        "null",
        "string"
       ]
      },
      "degraded": {
       "type": [
        "boolean",
        "null"
       ]
      },
      "payments": {
       "type": [
        "null",
        "number"
       ]
      },
      "totalPaid": {
       "type": [
        "null",
        "number"
       ]
      },
      "disclaimer": {
       "type": [
        "null",
        "string"
       ]
      },
      "notChecked": {
       "type": [
        "array",
        "null"
       ],
       "items": {
        "type": "string"
       }
      },
      "totalInterest": {
       "type": [
        "null",
        "number"
       ]
      },
      "firstAndLastPayments": {
       "type": [
        "array",
        "null"
       ],
       "items": {
        "type": "object",
        "properties": {
… (truncated)
```

## More

- Live health (JSON, refreshed every minute): https://www.zero.xyz/c/finance-calculators-loan-payment-amortization-87ec4b25/health.json
- [Zero catalog index](https://www.zero.xyz/llms.txt)
- [Other services from finance-calculators.x402tookit.com](https://www.zero.xyz/host/finance-calculators.x402tookit.com/llms.txt)