Mortgage Overpayment Calculator
Months cut from a mortgage and interest saved by paying extra each month.
Results
Months saved
52.4
Months
300.6
Months
248.2
Interest saved
14,438.65
What this tool does
Every euro of overpayment goes straight against the capital, so it stops earning the bank interest for the whole remaining term — which is why small regular overpayments early in a mortgage save so much more than the same amount paid late.
Formula
compares the term with and without the extra payment
Variables
| Symbol | Meaning | Unit |
|---|---|---|
b | Outstanding balance | — |
ar | Annual interest rate | % |
pm | Monthly payment | — |
ov | Extra paid each month | — |
SM | Months saved | — |
N1 | Months | — |
N2 | Months | — |
SI | Interest saved | — |
Worked example
- Outstanding balance150,000
- Annual interest rate3.5 %
- Monthly payment750
- Extra paid each month100
- Months saved52.4
- Months300.6
- Months248.2
- Interest saved14,438.65
Limitations
- This is an informational calculator, not personalised financial advice. Rates, fees, taxes and contract conditions vary between institutions and countries.
- The result is an estimate based only on the values you type. Real situations often include factors this calculator does not know about.
- The tool works with whatever currency you use for the inputs; it does not convert between currencies.
Frequently asked questions
Is overpaying always the best use of the money?
Not automatically. Overpaying earns you a guaranteed return equal to your mortgage rate, which is excellent when rates are high and unremarkable when they are low. Clear expensive debt first, keep an emergency fund intact, and check whether your contract charges an early repayment fee — several do, and it can wipe out the saving.