Loan and mortgage calculator API: monthly payment and schedule

$0.01 per call · failed calls are never charged · no account or API key needed

Monthly payment of an amortised loan or mortgage from the amount, the annual interest rate and the term, plus the total paid, the total interest and the first months of the repayment schedule (principal, interest and balance). Fixed rate, monthly payments. Use to compare loan offers or plan a mortgage.

When to use it

Work out the monthly payment of a mortgage or loan from amount, rate and term
Compare offers by total paid and total interest
Show the first months of the repayment schedule

Run it free (25 free calls) Buy credits by card (from $5) Example result (JSON)

Inputs

Name	Type	Description
`principal` (required)	number	Amount borrowed
`rate` (required)	number	Annual interest rate in percent, 0-100
`years`	number	Term in years (or give months)
`months`	integer	Term in months, instead of years
`rows`	integer	Schedule rows to return, 0-60 (default 3)

Request

Over HTTP, with a card key from /credits:

curl -H "Authorization: Bearer adt_…" "https://agent-data-tools.revmesh2074.workers.dev/calc/loan?principal=300000&rate=4.5"

Or one of your 25 free calls, no key:

curl "https://agent-data-tools.revmesh2074.workers.dev/calc/loan?principal=300000&rate=4.5&trial=1"

Without a key, the same URL answers 402 Payment Required with x402 and MPP terms, so an agent with a wallet pays per call in USDC (Base, Polygon, Arbitrum or Solana over x402; Base or Tempo over MPP) and retries.

Example result

{
  "monthlyPayment": 1520.06,
  "payments": 360,
  "totalPaid": 547220.13,
  "totalInterest": 247220.13,
  "schedule": [
    {
      "month": 1,
      "payment": 1520.06,
      "principal": 395.06,
      "interest": 1125,
      "balance": 299604.94
    }
  ]
}

From an AI agent (MCP)

Add the MCP server to Claude, Cursor or any MCP client. This tool is calc_loan, and the first 25 successful calls are free:

https://agent-data-tools.revmesh2074.workers.dev/mcp

Questions

Which loans does it model?

Fixed-rate, amortised loans with monthly payments; a 0% rate divides the amount evenly.

Can I give the term in months?

Yes, pass months instead of years.

How do I pay?

Each successful call costs $0.01; failed calls are not charged. The first 25 calls are free. Then pay with card credits (from $5) or per call in USDC over x402 or MPP. No account or API key is needed.