Loan, Mortgage & Interest Calculator

Compute the monthly payment, total interest, effective annual rate and a full amortization schedule for flat, annuity and descending-interest loans. All math runs locally in your browser — nothing is sent anywhere.

Inputs

Formatted: Rp 500.000.000

Summary

Monthly payment —
Total interest—
Total payment—
Payoff date—
Effective annual rate—nominal: —

How to use

  1. Enter the loan amount and pick a currency. The amount field accepts plain numbers (e.g. 500000000); a formatted preview appears below it.
  2. Set the annual interest rate as a percentage (e.g. 8.5 for 8.5%) and the loan term in years or months.
  3. Choose the interest type. Annuity = equal payments (standard mortgage). Descending = fixed principal each month. Flat = interest on the original principal for the whole term.
  4. Press Calculate to see the monthly payment, totals, payoff date, effective annual rate, a chart and the full amortization table. Toggle the table between first 12, yearly summary, and all rows.
  5. Export the schedule as CSV for spreadsheets, or press Print for a paper copy.
Formulas (r = annual rate / 12, n = total months):
Annuity: M = P · r(1+r)n / ((1+r)n − 1)
Descending: principal = P/n, interest = balance · r
Flat: M = P/n + P · r
Effective annual rate: (1 + IRRmonthly)12 − 1, where IRR is solved from the payment cash flow.