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Mortgage Repayment Calculator

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Estimate your monthly or yearly payment, total interest and full amortisation schedule. Adjust the term, rate or payment frequency and the numbers move as you type.

Your details

20% of price
%
Enter the annual interest rate shown in your mortgage illustration or example scenario.
years
Enter the number of whole years for the mortgage term.
Repayment type
Payment frequency
Loan amount
£600,000
Loan to value
80.0%
Estimated repayment payment
£3,595.49per month
Total interest
£478,646
Total repaid
£1,078,646
Loan amount
£600,000
Payments
300 × monthly
Balance owed at end
£0

Based on a 5.25% annual interest rate over 25 years, with monthly repayment payments.

Year-by-year mortgage breakdown
YearPrincipalInterestBalance
1£11,930£31,216£588,070
2£12,572£30,574£575,498
3£13,248£29,898£562,250
4£13,960£29,185£548,290
5£14,711£28,435£533,578
6£15,502£27,643£518,076
7£16,336£26,810£501,740
8£17,215£25,931£484,525
9£18,141£25,005£466,384
10£19,116£24,030£447,268
11£20,144£23,001£427,123
12£21,228£21,918£405,896
13£22,369£20,776£383,526
14£23,573£19,573£359,954
15£24,840£18,305£335,113
16£26,176£16,970£308,937
17£27,584£15,562£281,353
18£29,068£14,078£252,285
19£30,631£12,515£221,654
20£32,278£10,867£189,376
21£34,014£9,132£155,361
22£35,844£7,302£119,518
23£37,771£5,374£81,746
24£39,803£3,343£41,944
25£41,944£1,202£0

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How to use this calculator

Pick your currency, then enter the property price and your deposit and type the annual interest rate and mortgage term. The payment figure updates instantly, and the schedule below shows how each year's payments split between capital and interest.

Payment frequency switches between the two ways of settling the loan. Monthly is how a residential mortgage is normally collected; yearly charges a full year of interest before anything comes off the capital, so the same rate and term cost more overall.

Interest-only mode charges the rate against the full balance every period, so the capital never reduces and the amount you borrowed is still owed at the end of the term.

What do I need to enter?

  • Property price — what the home costs, before any deposit. Used with the deposit to work out the loan and the loan-to-value.
  • Deposit — the cash you put in. The loan amount is the price minus this.
  • Annual interest rate — the yearly rate from your lender's illustration, 0% to 100%. It is held fixed for the whole term.
  • Mortgage term — whole years from 1 to 50.
  • Repayment type — Repayment clears the loan by the end of the term; Interest only pays the interest alone and leaves the loan outstanding.
  • Payment frequency — Monthly (12 payments a year) or Yearly (one).

What do the results show?

  • Estimated payment — the main figure: what you pay each month or year.
  • Total interest and total repaid — what the loan costs over the whole term, and the sum of every payment.
  • Loan amount and loan to value — the amount borrowed, and that amount as a percentage of the property price.
  • Balance owed at end — zero on a repayment mortgage, the full loan on an interest-only one.
  • Amortisation schedule — a table and chart of how each year's payments split between capital and interest.

How mortgage repayments are calculated

The calculator works out the loan amount by subtracting the deposit from the property price. For repayment mortgages, each payment covers interest and part of the loan balance. For interest-only mortgages, each payment covers interest only and the original loan amount remains outstanding at the end of the term.

  • P — loan amount after deposit
  • r — the annual interest rate you enter, as a decimal (5.25% is 0.0525)
  • m — payments per year: 12 for monthly or 1 for yearly
  • i = r / m — interest rate per payment period
  • n — total number of payments, the mortgage term in years × m
repayment payment = P × i(1 + i)ⁿ ÷ ((1 + i)ⁿ − 1)
  • If i = 0, repayment payment = P ÷ n
  • interest-only payment = P × i
  • For yearly payments, m = 1 and the same formula applies with one period per year

With £600,000 at 5.25% over 25 years, the repayment formula resolves to about £3,595.49 a month and roughly £478,646 of interest over the life of the loan. Paid once a year instead, the same loan costs about £43,644.39 a year and more interest overall. An interest-only payment on the same loan is £600,000 × (0.0525 ÷ 12), about £2,625 a month, with the full £600,000 still owed at the end.

The calculator uses the same nominal values in whichever currency is selected. Selecting a currency changes labels and number formatting only; it does not convert amounts using exchange rates.

Why is this an illustrative estimate?

The figure assumes the rate you enter holds for the whole term and that every payment is made on time. It excludes arrangement and product fees, valuation and legal costs, buildings and life insurance, Stamp Duty and other taxes, early-repayment charges, overpayments and payment holidays. If your rate is variable, tracker, discounted or fixed for an initial period only, your payments will change when the rate does. Use it to compare scenarios, not as a quote — your lender's illustration and mortgage offer set the actual payments and total cost.

Frequently asked questions

What is the difference between repayment and interest-only?

On a repayment mortgage each payment covers the interest for that period plus a slice of the loan balance, so the balance falls to zero by the end of the term. On an interest-only mortgage each payment covers only the interest, so the balance never reduces and the full amount you borrowed is still owed when the term ends. Repayment is the norm for a residential mortgage; interest-only is mostly used for buy-to-let.

Why does interest-only leave the original loan amount outstanding?

An interest-only payment is exactly the interest charged on the balance for that period and nothing more. Because none of the payment is put towards the capital, the balance stays at the amount you first borrowed for the whole term. At the end you either repay it in full from savings, investments or the sale of the property, or you remortgage. This calculator does not model a repayment vehicle or any overpayments.

Can I enter any mortgage term?

Yes. Type any whole number of years from 1 to 50 in the Mortgage term field. The calculator is illustrative, so it is not limited to common terms like 25 or 30 years and it does not check whether a lender would offer the term you enter. Fractional values such as 25.5 are rejected — enter whole years only.

Why does a longer mortgage term change the payment and total interest?

A longer term spreads the loan over more payments, so each payment is smaller. But interest is charged on the outstanding balance every period, and a longer term keeps the balance high for longer, so the total interest paid over the life of the loan is larger. A shorter term reverses this: bigger payments, less interest overall.

Can I enter an exact interest rate?

Yes. Type the annual interest rate to as many decimal places as your illustration or example scenario shows — 4.79, 5.25, 6.14 and so on. The full figure is used in the calculation; nothing is rounded before the payment and schedule are worked out.

Why does the calculator allow a 0% interest rate?

A 0% rate is valid for illustration — for instance, to see what the payment would be if only the capital were repaid. With no interest, a repayment payment is simply the loan amount divided by the number of payments, and an interest-only payment is zero with the whole balance still outstanding at the end of the term.

Why might my actual mortgage payments differ from this estimate?

The estimate assumes one fixed interest rate for the entire term and payments made exactly on schedule. A real mortgage usually has an initial fixed, tracker or discounted period and then reverts to a different rate, and the payment is recalculated whenever the rate changes. Lenders also apply their own day-count and rounding rules, and add arrangement fees, valuation and legal costs, buildings insurance and any early-repayment charges. Your lender’s illustration and mortgage offer are the figures that count.

What does loan-to-value (LTV) mean?

Loan-to-value is the loan amount as a percentage of the property price — a £600,000 loan on a £750,000 property is 80% LTV. A larger deposit means a lower LTV, which usually unlocks lower interest rates. The calculator shows the LTV for the price and deposit you enter.

How does monthly versus yearly payment frequency change the calculation?

The quoted rate is a nominal annual rate. Monthly payments are charged one twelfth of it each month over term × 12 payments; yearly payments are charged the full annual rate once over term × 1 payments. Because a yearly schedule lets interest build on the balance for a full year before anything is repaid, the same rate and term cost more in total interest when paid yearly.

What does changing the currency do?

It changes the currency symbol and number formatting on every field and result — nothing else. The property price, deposit, loan amount, payment and schedule keep the same nominal numbers. There is no exchange-rate conversion: 750,000 stays 750,000 whether it is shown as pounds, dollars or euros.

Is this mortgage advice or a lender quote?

No. It is an illustrative calculation of the standard amortisation formula. It is not mortgage advice, an affordability assessment, a decision in principle, an eligibility check or a quote, and it does not recommend a lender, product, term or deposit. For advice, speak to a mortgage broker or a lender.

Last updated 25 October 2026.