Fill in the figures, then click Work out the saving.
Result
With and without overpaying
| Line | No overpayment | Overpaying |
|---|
If you overpaid a different amount each month
| Per month | Interest saved | Mortgage-free after |
|---|
What to do
| Step | What it means |
|---|
What it does, and what it leaves to you
- Covers: a repayment mortgage at one fixed rate, a regular monthly overpayment, a one-off lump sum, a comparison with saving the same money, the free overpayment allowance, and the monthly overpayment needed for a target payoff.
- Gives: interest saved, time saved, mortgage-free date, how overpaying compares with saving at the original end date, and outcomes at other overpayment sizes.
- Not decided: interest-only or offset mortgages, variable rates changing, fees, tax on savings interest, your lender's actual early repayment charge terms, how your lender applies overpayments, and anything that changed after this was written.
Common questions
How much interest does overpaying my mortgage save?
It depends on the balance, rate and term. On £200,000 at 4.5% over 25 years, overpaying £200 a month saves about £36,000 of interest and clears the loan six years early. Enter your own figures to see yours.
Is it better to overpay my mortgage or save?
If your mortgage rate is higher than the after-tax rate on your savings, overpaying usually wins on paper. But savings stay accessible and mortgage overpayments do not come back out, so keep an emergency fund first. The calculator compares the two at the original end date.
How much can I overpay without an early repayment charge?
Most fixed and discounted deals let you overpay up to 10% of the balance a year without charge. Above that, the excess may be charged at 1% to 5%. Check your mortgage offer or ask your lender.
Does overpaying shorten the term or reduce the monthly payment?
It depends on the lender. This calculator assumes your monthly payment stays the same and the term shortens, which is what saves the most interest. Ask your lender to confirm how they apply overpayments.
What if my rate changes when my deal ends?
The calculation uses one rate for the whole term. Re-run it with your new rate after a remortgage; the balance and remaining term are the inputs that matter.
Is my data uploaded anywhere?
No. Everything is calculated in your browser and nothing is sent.