Irish Calculators
Loans & mortgages

Mortgage Payoff Time Calculator

Calculate how long a mortgage balance takes to repay with your stated monthly payment. The result is a payoff projection, not a lender redemption statement or a fixed-rate contract term.

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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

This payoff estimate starts with the principal currently outstanding and asks how long a fixed monthly payment would take to clear it. It follows the balance payment by payment, so the final instalment can be smaller than the regular amount.

Iterate balance × (1 + monthly rate) − payment until cleared, reducing the final payment to the amount actually due.

  1. Accrue one month of interest

    The annual nominal percentage is divided by 12. Each month, that rate applies to the opening principal; the calendar dates label the schedule without changing the interest charge.

  2. Apply the chosen payment

    Interest is covered first and the remainder reduces principal. A payment that cannot cover interest is rejected, as is a scenario that cannot clear within 1,200 months.

  3. Clear the final balance

    Once the amount due is smaller than the normal payment, only that balance and its interest are paid. The table records the reduced final instalment and its date.

Worked example: Three full payments and a partial fourth

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

The first example owes €1,000 at zero interest and pays €300 monthly. Three payments clear €900, leaving €100 for a fourth. Total interest remains zero, and the final payment is €100 rather than another €300.

Loan balance (€)
1000
Annual nominal interest rate (%)
0
Fixed monthly payment
300
Start of first interest period
2026-01-01

Expected result

Payments until payoff
4
Final payment
€100.00
Total interest
€0.00
Worked example: One payment at one percent monthly

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

Loan balance (€)
1000
Annual nominal interest rate (%)
12
Fixed monthly payment
1010
Start of first interest period
2026-01-01

Expected result

Payments until payoff
1
Final payment
€1,010.00
Total interest
€10.00

Understanding your result

Payments until payoff is a count of monthly instalments. Dividing it by 12 gives the displayed years; it does not measure actual days between payment dates.

Compare payment scenarios using both interest and duration. A projected payoff date is not a lender redemption figure, which can include accrued daily interest or contractual charges.

Questions you might have

Can I enter a payment below the monthly interest?

No. Such a payment does not repay the principal, so no finite payoff date exists under this model.

Choosing the right inputs

Loan balance
Enter the principal immediately before the first modelled interest period. Exclude a separate settlement charge unless you deliberately intend to finance it.
Fixed monthly payment
Use the amount applied to this mortgage each month. Insurance or other charges collected alongside the repayment should not inflate this figure.
Start of first interest period
This is the start of the first interest period, not the first repayment date. The first scheduled payment is one calendar month later.

Common mistakes to avoid

  • Do not enter a fee-inclusive APR as though it were the contractual nominal rate.
  • A variable-rate history or irregular first period cannot be recreated by changing the start date alone.

Assumptions to check

  • Fixed nominal rate and equal monthly periods; this is not a lender redemption statement.

Sources and method

Read our calculation and testing approach.