Irish Calculators
Loans & mortgages

Loan Amortisation Schedule Calculator

Enter a balance, fixed rate and term to see an amortisation table month by month. It assumes equal monthly interest periods and does not model irregular daily accrual or a balloon settlement.

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Your numbers

€
Use the principal owed before the next interest period.
%
Monthly interest is the annual nominal rate divided by 12. This is not a fee-inclusive APR.
Your figures stay on this device.

How the calculation works

Build a monthly schedule showing how a conventional loan balance falls over its remaining term. Interest and principal are separated in each payment, with a choice of full-precision calculations or monthly cent rounding.

Payment = P × i / [1 − (1 + i)^−n]; at i = 0, payment = P/n. Interest = balance × i; principal = payment − interest; the last payment clears the balance.

  1. Calculate regular payment

    Apply the annuity formula to principal, monthly rate and payment count. At zero interest, divide principal by the number of months.

  2. Split each payment

    Multiply opening balance by monthly rate for interest. The payment remaining after interest reduces principal and determines the next opening balance.

  3. Clear the final balance

    Repeat the calculation, limiting the final payment to remaining principal and interest. Inspect total interest alongside the month-by-month allocation.

Worked example: Interest-free amortization

Sample inputs demonstrate the method. They are not a forecast or product offer.

The first example borrows €1,200 at zero interest over twelve months. Principal divided by twelve gives €100 monthly. Every payment repays principal, interest is zero and total payments equal €1,200.

Loan balance (€)
1200
Annual nominal interest rate (%)
0
Remaining term (months)
12
Start of first interest period
2026-01-01
Schedule rounding
Full precision; display cents

Expected result

Regular payment
€100.00
Total interest
€0.00
Total payments
€1,200.00
Worked example: Two payments at 1% monthly

Sample inputs demonstrate the method. They are not a forecast or product offer.

Loan balance (€)
1000
Annual nominal interest rate (%)
12
Remaining term (months)
2
Start of first interest period
2026-01-01
Schedule rounding
Full precision; display cents

Expected result

Regular payment
€507.51
Total interest
€15.02
Total payments
€1,015.02

Understanding your result

Early payments usually contain more interest because the balance is larger. At a fixed rate, more of each regular payment goes toward principal as the balance declines.

This is a regular monthly model. Actual-day accrual, irregular first periods, extra fees and balloon arrangements can produce different results on a lender's statement.

Questions you might have

Why can the last payment differ?

The final payment clears the outstanding principal and interest. In cent-rounding mode it also absorbs accumulated rounding differences.

Can I use a daily-interest bank statement?

The dates here do not change monthly accrual. A lender using actual-day interest or an irregular first period can produce a different schedule.

Choosing the right inputs

Loan balance
Use principal outstanding before the first interest period. Do not include future interest, which the schedule calculates separately.
Annual nominal interest rate
Enter the annual nominal rate. Monthly interest uses one twelfth of it; a fee-inclusive APR or effective annual rate can represent a different convention.
Schedule rounding
Full precision keeps unrounded internal amounts. Cent mode rounds monthly interest and payments, with accumulated differences absorbed by the final payment.
Start of first interest period
This dates the start of the first interest period. Calendar labels do not change interest according to the number of days in each month.

Common mistakes to avoid

  • Do not assume displayed cent rounding means a lender rounds every internal amount identically.
  • Do not use a fully amortising schedule for a contract containing an unmodelled final balloon.

Assumptions to check

  • Regular equal monthly interest periods; no daily or irregular first-period accrual. Start date labels the calendar only.
  • This is a conventional amortizing loan, not a PCP, balloon or leasing settlement.

Sources and method

Read our calculation and testing approach.