Mortgage Meadow

Mortgage overpayment calculator

Put in what you owe, the rate you are on and how long is left. It works out the date the mortgage clears, how much of the term an overpayment takes off, and what that saves in interest. Nothing is stored and nothing is sent anywhere — the arithmetic runs in this browser.

Leave at 0 if there isn’t one.
Mortgage-freeJune 2044instead of August 2048
Sooner by4y 2moff the remaining term
Interest saved£24,445£90,011 instead of £114,456
Contractual payment£1,115.37a month, before anything extra

Interest is applied monthly here, to the balance at the start of each month, and payments are treated as falling at the end of it. Many lenders calculate interest daily, so their figure and this one will never match to the penny. Fees are excluded, the rate is held where you put it, and an overpayment is treated as shortening the term rather than reducing the monthly payment — the common arrangement, but not the only one. The full model.

Then watch the date actually move

A calculator answers the question once. The app keeps the answer true: log what you pay each month, and the mortgage-free date moves with it. Free to see where your mortgage stands.

Start freeGet it on Google PlayGuides

What the calculator is doing

It treats your mortgage as starting today at the balance you entered, and runs the remaining term forward. That is the same thing the app does for somebody part-way through a mortgage: replay from a balance you can state rather than invent the years of payments behind it. Interest is applied monthly, and each payment is treated as falling at the end of the month it settles — so the first one lands a month from now, not today.

The overpayment is applied on top of the contractual payment and reduces the balance directly. The term shortens because the balance runs out sooner; the monthly payment stays where it was. Interest saved is the difference between the total interest on the contractual schedule and the total interest with the overpayments in — both figures are shown, so the saving is a subtraction you can check rather than a number you have to take on trust.

Where it will differ from your lender

Interest is applied monthly here; many lenders calculate it daily. Over a full term the difference is real but small, and it means the two figures will never match to the penny. Fees are excluded — product fees, valuation fees and any charge for making the overpayment itself. The rate is held where you put it, because nobody can forecast rate movements, and a fixed deal that reverts will change the arithmetic on the day it reverts. The full model is written out here, including the parts that are deliberately left out.

Questions

How much does overpaying a mortgage actually save?
It depends on the rate, the balance and how long is left, which is why the figure has to be worked out rather than quoted. An overpayment comes straight off the balance, so every month afterwards accrues interest on a smaller number — the saving compounds, and the same £100 a month is worth far more with twenty years to run than with three.
Does overpaying reduce the term or the monthly payment?
Both arrangements exist and lenders differ. This works it out as a shorter term, because that is the common arrangement and the one that saves the most interest. If yours reduces the monthly payment instead, the balance still falls but the term does not move — check which your lender does before relying on a date.
Is there a limit on what I can overpay?
Often, on a fixed deal. Most fixed offers allow a percentage of the balance each year with no charge and bill an early-repayment charge on the excess. That figure is separate from the saving, and it is worked out on the early repayment charge calculator.
When will I be mortgage-free?
The date above, on the figures entered. It moves whenever the balance, the rate or the payments change, so it is a projection from today rather than a promise — the arithmetic is fixed, the inputs are not.

This is a calculator, not financial advice, and the figures are estimates worked out from what you entered. It does not recommend a course of action, name a lender or tell you what your mortgage ought to be — see the early repayment charge calculator for what an overpayment above your allowance would cost, and the guides for how the mechanics work.

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