Loan & Mortgage Calculator API

Monthly payment, total interest and full amortization schedule for loans and mortgages. Down payment, extra payments, weekly/biweekly/monthly frequency and yearly summaries.

Authentication & base URL

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Endpoints

GET `/v1/loan`

Calculate loan or mortgage

Parameter	In	Description	Example
`amount`	query	Loan amount (or use price + down_payment)	`200000`
`price`	query	Property price (mortgages)
`down_payment`	query	Down payment (with price)
`rate` *	query	Annual interest rate in % (e.g. 4.5)	`4.5`
`years`	query	Term in years (or months)	`30`
`months`	query	Term in months (instead of years)
`frequency`	query	monthly (default), biweekly, weekly, quarterly or annually	`monthly`
`extra_payment`	query	Extra principal paid every period	`0`
`schedule`	query	summary (default), yearly or full	`yearly`
`monthly_costs`	query	Optional monthly insurance/taxes added to the payment

Example

GET /v1/loan?amount=200000&rate=4.5&years=30&frequency=monthly&extra_payment=0&schedule=yearly

{
  "loanAmount": 200000,
  "annualRate": 4.5,
  "frequency": "monthly",
  "payments": 360,
  "paymentAmount": 1013.37,
  "totalInterest": 164813.42,
  "totalPaid": 364813.42,
  "actualPayments": 360,
  "timeSavedPayments": 0,
  "schedule": [
    {
      "year": 1,
      "principal": 3226.45,
      "interest": 8934,
      "balance": 196773.55
    },
    {
      "year": 2,
      "principal": 3374.68,
      "interest": 8785.77,
      "balance": 193398.87
    },
    {
      "year": 3,
      "principal": 3529.71,
      "interest": 8630.75,
      "balance": 189869.16
    },
    {
      "year": 4,
      "principal": 3691.86,
      "interest": 8468.58,
      "balance": 186177.3
    },
    {
      "year": 5,
      "principal": 3861.46,
      "interest": 8298.99,
      "balance": 182315.83
    },
    {
      "year": 6,
      "principal": 4038.85,
      "interest": 8121.59,
      "balance": 178276.97
    },
    {
      "year": 7,
      "principal": 4224.41,
      "interest": 7936.04,
      "balance": 174052.57
    },
    {
      "year": 8,
      "principal": 4418.48,
      "interest": 7741.97,
      "balance": 169634.09
    },
    {
      "year": 9,
      "principal": 4621.46,
      "interest": 7538.98,
      "balance": 165012.64
    },
    {
      "year": 10,
      "principal": 4833.77,
      "interest": 7326.68,
      "balance": 160178.87
  …

Monthly payment, total interest and full amortization schedule for loans and mortgages. Down payment, extra payments, weekly/biweekly/monthly frequency and yearly summaries.

Use cases

Real estate and mortgage websites, car loan calculators, fintech apps, personal finance tools, lead generation forms.

Why this API

Standard amortization formula, rounded to cents, with the full schedule or a yearly summary.
Extra payments: see how many payments and how much interest you save.
Instant: computed on a global edge network.

Pricing

Free plan with 500 calls per month, then Pro (25,000 calls for $4.99/month) and Ultra (150,000 calls for $14.99/month). See all plans.