Where does my mortgage payment actually go?
Already have a repayment mortgage? Enter what it looks like today to see how much of your normal payment goes to interest, how much reduces the balance, and how that changes over time.
Money With Clo doesn’t receive or store the mortgage figures you enter. The calculation happens in your browser, and we don’t ask for your name, lender, address, account number or bank details. Normal site analytics may record that this page was visited, but not the mortgage numbers you type into this calculator.
Your mortgage today
After your current deal
Your current rate is used up to the end of the deal you entered. For any projection that goes beyond your current deal, we need to make an assumption about your next mortgage rate.
Why 5.5%? Average UK two- and five-year fixed rates were around 5.6% in late August 2026. The market moves, so treat this as a starting assumption rather than a forecast.
How much are you actually paying off?
How does the split change over time?
How much of each payment reduces the balance?
How your payments change
Each bar is one point in your projected mortgage. The total bar can change after your current deal ends because the future payment is recalculated using the assumption below.
Where could you be when your current deal ends?
What if I paid a little extra?
See what a small regular overpayment could change between now and the end of your current deal.
How I make mortgage overpayments
I use Sprive, a mortgage overpayment app that can put shopping rewards and other money towards your mortgage. I joined in June 2026, have used it myself, and I wrote a proper review covering what I like, what I would watch out for, and what happened when I won £2,000 in its referral prize draw.
Referral disclosure: I have a Sprive referral link and Sprive rewards me for qualifying referrals through it. The calculator above does not depend on using Sprive.
I wanted to see what my mortgage payment was actually doing.
Once a year I sit down with my mortgage statement and work out how much of everything I’ve paid actually reduced the balance and how much went on interest. I find the changing split weirdly satisfying, but it shouldn’t require a spreadsheet and an unnecessary amount of concentration. So I built this instead.
How much of my mortgage payment is interest?
On a repayment mortgage, each normal payment has two jobs. One part pays the interest charged on the balance you still owe. The rest reduces the mortgage itself, often called the capital or principal.
Because interest is charged on the outstanding balance, the split usually changes over time. As the balance falls, less interest is due and more of the payment can go towards reducing the mortgage. That is why the same monthly payment can feel as though it is making much more progress later in the term.
How much of my mortgage do I actually pay off each year?
The easiest way to see it is to add up the capital part of each payment across the year. The calculator does that month by month for you, so the 12-month result shows the total you pay, the estimated interest portion, and the amount that actually reduces the balance.
This is the calculation I used to do manually from my own mortgage statement every year. I wanted the answer without needing to build another spreadsheet.
Why can the split change when my fixed deal ends?
Your current rate only tells us what happens while that rate applies. If your deal ends before the mortgage does, any longer-term projection needs another rate assumption. Rather than hiding that assumption, this calculator puts it near the top of the results and lets you change it.
The future rate is not a prediction. It is there so you can see how a different rate could change the monthly payment and the interest-versus-capital split.
Does overpaying change how much interest I pay?
Potentially, yes. An overpayment reduces the mortgage balance sooner, which can mean less interest is charged afterwards. The small experiment above only models regular extra payments until the end of your current deal. It deliberately does not try to replace a full overpayment calculator.
Before actually overpaying, check your lender’s rules, including any Early Repayment Charge or overpayment limit that applies to your mortgage.
Mortgage payment breakdown FAQs
What is the difference between mortgage interest and capital?
Capital is the mortgage balance you owe. Interest is the charge your lender makes for lending you that money. On a repayment mortgage, each normal monthly payment usually covers both.
Why does more of my mortgage payment go to capital over time?
As you repay the mortgage, the outstanding balance falls. If the interest rate stays the same, the interest charged on that smaller balance also falls, leaving more of the payment to reduce the capital.
Is this calculator exact?
No. It is an illustrative monthly model. Lenders can calculate interest daily, use different payment dates and rounding, and apply product-specific rules. Use your lender’s statement for exact account figures.
Does this work for interest-only mortgages?
No. V1 is designed for capital-and-interest repayment mortgages. On an interest-only mortgage, the normal monthly payment generally covers interest without reducing the capital balance.
Does Money With Clo store my mortgage details?
No. The figures you enter into this calculator are processed in your browser and are not sent to Money With Clo. Normal site analytics can record a page visit, but this calculator does not send your mortgage input values to analytics.
Can I see what happens if I overpay?
Yes. The small overpayment experiment shows what a regular extra payment could change by the end of your current deal. A separate full Mortgage Overpayment Calculator will cover lump sums, longer-term interest savings and term reduction.
How the estimate works
- Designed for UK capital-and-interest repayment mortgages.
- It models interest monthly using your annual rate divided by 12. Your lender may calculate interest daily, use different payment dates or apply different rounding, so statement figures can differ slightly.
- Your current payment is used until the end of the deal you enter. After that, the calculator recalculates a payment using the remaining balance, remaining term and the future-rate assumption you choose.
- The future rate is only an illustration. It is not a forecast of the rate you will actually receive.
- The overpayment experiment ignores Early Repayment Charges and lender-specific overpayment limits. Check your mortgage terms before making an overpayment.
- This is an educational estimate, not personalised financial advice or a lender quote.