Docs/APIs/Loan Calculator

Loan Calculator

Calculate loan payments

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Overview

Loan Payment Calculator works by using the loan amount, interest rate, and loan term to calculate the monthly loan payment, total interest, and more.

Endpoint

One host, one path per API. The block below shows this call in four languages; every one of them is the same HTTP request. Making requests covers the timeouts, retries and parameter rules that apply to all of them. The SDKs wrap the same call in a typed client.

POSThttps://api.apiverve.com/v1/loanpaymentcalculator
curl -X POST https://api.apiverve.com/v1/loanpaymentcalculator \
  -H "x-api-key: your_api_key_here" \
  -H "Content-Type: application/json" \
  -d '{
  "loanAmount": 32000,
  "interestRate": 8.5,
  "loanTerm": 6
}'
const res = await fetch('https://api.apiverve.com/v1/loanpaymentcalculator', {
  method: 'POST',
  headers: {
    'x-api-key': 'your_api_key_here',
    'Content-Type': 'application/json',
  },
  body: JSON.stringify({
  "loanAmount": 32000,
  "interestRate": 8.5,
  "loanTerm": 6
}),
});

if (!res.ok) throw new Error(`${res.status} ${await res.text()}`);

const { data } = await res.json();
console.log(data);
import requests

res = requests.post(
    "https://api.apiverve.com/v1/loanpaymentcalculator",
    headers={"x-api-key": "your_api_key_here"},
    json={
    "loanAmount": 32000,
    "interestRate": 8.5,
    "loanTerm": 6
},
    timeout=15,
)
res.raise_for_status()

print(res.json()["data"])
package main

import (
	"fmt"
	"io"
	"net/http"
	"strings"
)

func main() {
	body := strings.NewReader(`{
  "loanAmount": 32000,
  "interestRate": 8.5,
  "loanTerm": 6
}`)
	req, _ := http.NewRequest("POST", "https://api.apiverve.com/v1/loanpaymentcalculator", body)
	req.Header.Set("Content-Type", "application/json")
	req.Header.Set("x-api-key", "your_api_key_here")

	res, err := http.DefaultClient.Do(req)
	if err != nil {
		panic(err)
	}
	defer res.Body.Close()

	out, _ := io.ReadAll(res.Body)
	fmt.Println(string(out))
}

Replace your_api_key_here with the key from your dashboard. When the inputs arrive as a list rather than one at a time, batch requests run up to 200 of them through this same API in a single call.

Authentication

Send your key in the x-api-key header. That is the only auth step — there is no token exchange and no per-endpoint scope to configure. Authentication covers creating, rotating and revoking keys.

401 is the only auth verdict

A 401 means the key is missing, invalid or expired. A 403 means the key is valid but not permitted here — blocked by a key restriction or an IP allow-list. Running out of credits is a 429.

Parameters

Sent as JSON in the request body. Premium parameters are accepted on every plan but only take effect on plans that include them.

ParameterTypeDescription
loanAmountRequirednumberThe loan amount
range 0–∞
interestRateRequirednumberThe interest rate (percentage)
range 0–100
loanTermRequiredintegerThe loan term in years
range 1–50
downpaymentOptionalnumberAmount paid up front, subtracted from the loan amount before interest is applied
range 0–∞

Response

Every API returns the same three top-level keys, so one response handler covers your whole integration: status, error and data. Only data changes shape. Response format covers the envelope, the other output formats and how premium fields are withheld.

Sample response
{
  "status": "ok",
  "error": null,
  "data": {
    "loanAmount": 32000,
    "downpayment": 0,
    "interestRate": 8.5,
    "loanTerm": 6,
    "monthly_payment": 568.91,
    "total_interest_paid": 8961.4,
    "total_payment": 40961.52,
    "interestRatio": 21.88,
    "formatted": {
      "loanAmount": "$32,000.00",
      "monthlyPayment": "$568.91",
      "totalInterestPaid": "$8,961.40",
      "totalPayment": "$40,961.52"
    },
    "amortization_schedule": [
      {
        "month": 1,
        "interest_payment": 226.67,
        "principal_payment": 342.24,
        "remaining_balance": 31657.76
      },
      {
        "month": 2,
        "interest_payment": 224.24,
        "principal_payment": 344.67,
        "remaining_balance": 31313.09
      },
      {
        "month": 3,
        "interest_payment": 221.8,
        "principal_payment": 347.11,
        "remaining_balance": 30965.99
      }
    ]
  }
}

Response fields

Paths are relative to data. Premium fields are absent rather than zeroed on plans that do not include them, so check for presence instead of comparing to 0.

FieldTypeExampleDescription
loanAmountnumber32000Original loan amount in dollars
downpaymentnumber0Down payment amount applied to loan
interestRatenumber8.5Annual interest rate as percentage
loanTermnumber6Loan repayment period in years
monthly_paymentnumber568.91Required monthly loan payment amount
total_interest_paidnumber8961.4Total interest paid over loan term
total_paymentnumber40961.52Total amount paid over entire loan term
interestRationumber21.88Percentage of total payment allocated to interest
formattedobject{...}
loanAmountPremiumstring"$32,000.00"Formatted loan amount with currency symbol
monthlyPaymentPremiumstring"$568.91"Formatted monthly payment with currency symbol
totalInterestPaidPremiumstring"$8,961.40"Formatted total interest paid with currency
totalPaymentPremiumstring"$40,961.52"Formatted total payment amount with currency
amortization_schedulePremiumarray[3]Month-by-month breakdown of payments and balances
monthPremiumnumber1Payment period month number
interest_paymentPremiumnumber226.67Interest portion of monthly payment
principal_paymentPremiumnumber342.24Principal portion of monthly payment
remaining_balancePremiumnumber31657.76Outstanding loan balance after payment

Errors

Read the HTTP status first, then error for the specific reason. The body names the parameter that has to change. Error handling covers the full status list and which of them are worth retrying.

StatusMeaningWhat to do
400Input was rejectedRead error; it names the parameter.
401Key missing or invalidCheck the header name and the key value.
403Key valid, but not permittedA key restriction or IP allow-list; see key scoping.
429Rate limited, or out of creditsRead error to tell them apart; see rate limits.

Use cases

Financial Planning
Plan financial budgets by using the Loan Payment Calculator API to calculate loan payments. Use the data to manage expenses and savings through your products
Loan Analysis
Analyze loan terms by using the Loan Payment Calculator API to calculate loan payments. Use the data to compare loan options and choose the best one
Debt Management
Manage debt by using the Loan Payment Calculator API to calculate loan payments. Use the data to create repayment plans for your customers
Budgeting Tools
Create budgeting tools by using the Loan Payment Calculator API to calculate loan payments. Use the data to estimate monthly expenses and savings

Other ways to use Loan Calculator

Set up Loan Calculator on APIVerve, or reach the same source a different way. Your APIVerve account and credits work on all of them — one key, one balance.

Give it to an AI agentConnect over MCP and your agent calls it as a native tool — Claude, Cursor, ChatGPT.VerveKitReference →
Use it in Google Sheets or ExcelA =VERVE() formula fills a column — no script, no export, recalculates in place.VerveSheetsReference →
Ground an agent on itA cited, machine-checkable fact your model can't produce on its own.VerveContextReference →

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