How to Work Out the True Cost of a Mortgage: Fees, Interest and Hidden Charges
Published 12th of January 2012·Updated 29 April 2026
Reviewed by: Reviewed for accuracy April 2026
The true cost of a mortgage is not just the interest rate. Arrangement fees, valuation fees, legal costs and insurance can add thousands of pounds to the total amount you pay over the life of the loan. To compare mortgages accurately, you need to add every cost together and look at what you will actually pay from start to finish.
Short Summary
The interest rate on a mortgage only tells part of the story. A deal with a low rate but a £2,000 arrangement fee can cost more over a two-year fix than one with a slightly higher rate and no fee.
The Annual Percentage Rate of Charge (APRC) is a useful starting point because it includes most fees in a single figure. However, it assumes you keep the mortgage for its full term, so it is not always the best measure for shorter deals.
To find the true cost, multiply your monthly payment by the number of months in the deal, then add all upfront fees. Subtract any cashback the lender offers. This gives you the total cost for the initial deal period, which is the most useful comparison figure.
Once your initial deal ends, your lender will move you to their Standard Variable Rate (SVR), which is typically much higher. Factor in the cost of remortgaging every two to five years when planning your long-term budget.
What fees do you pay when taking out a mortgage?
Mortgage fees fall into two categories: lender fees and third-party fees. Both add to the total cost and both need to be budgeted for.
Common lender fees include the arrangement fee (also called a product fee), which can range from nothing to over £2,000 depending on the deal. Some lenders charge a booking fee of £100 to £300 to reserve a rate while your application is processed. A valuation fee covers the lender's assessment of the property and typically costs £150 to £1,500 depending on the property value.
Third-party costs include conveyancing solicitor fees (typically £800 to £1,500), the Land Registry registration fee (which varies by property price), and a Stamp Duty Land Tax payment if you are buying above the current threshold. Buildings insurance is also a condition of most mortgage offers.
How do arrangement fees affect the total cost?
A high arrangement fee can wipe out the saving from a lower interest rate. For example, a mortgage with a rate of 4.0% and a £1,999 arrangement fee versus a mortgage with a rate of 4.3% and no fee may cost a similar amount over a two-year deal period.
| Example (£200,000 mortgage, 2-year fix) | Rate | Fee | Approx. monthly payment | Total 2-year cost |
|---|---|---|---|---|
| Deal A | 4.0% | £1,999 | £955 | £24,919 |
| Deal B | 4.3% | £0 | £984 | £23,616 |
In this example, the lower-rate deal is actually more expensive over two years once the fee is included. Always do this calculation before choosing a mortgage.
You can add the arrangement fee to the loan to avoid paying it upfront, but be aware that you will then pay interest on it for the full mortgage term, which increases the overall cost further.
How does the interest rate type affect what you pay?
A fixed rate mortgage locks your interest rate for an agreed period (typically 2, 3 or 5 years). Your monthly payment stays the same throughout the fix, making it straightforward to budget. After the fix ends, your lender moves you to their SVR, which is almost always higher.
A variable rate mortgage (either a tracker or a discount deal) means your payments can go up or down. Tracker mortgages follow the Bank of England base rate directly, usually at a set margin above it. Discount mortgages offer a reduction off the lender's SVR, which the lender can change at any time.
For the purpose of calculating total cost, use the current rate to estimate payments on a variable deal, but build in a buffer in case rates rise.
What is the APRC and is it useful for comparing mortgages?
The Annual Percentage Rate of Charge (APRC) is a standardised figure that lenders must display by law. It includes the interest rate and most fees, expressed as an annual percentage. The FCA requires lenders to show it on all mortgage illustrations.
The APRC is useful for a rough comparison between deals, but it has limitations. It assumes you hold the mortgage for its entire term and reverts to the SVR after the initial deal. In practice, most borrowers remortgage every two to five years, so the APRC can be misleading. The better measure for most borrowers is the total cost over the initial deal period, calculated as described above.
What ongoing costs should you budget for?
Beyond the mortgage itself, you need to budget for buildings insurance (required by your lender), contents insurance, and potentially life insurance or mortgage protection insurance. These are not included in mortgage calculations but are a real cost of homeownership.
If you use a mortgage broker, they may charge a fee of £300 to £500, though many brokers are paid by the lender through a procuration fee and charge nothing to you directly. A broker with access to the whole of the market can often find deals not available on the high street, which may offset their fee many times over.
Should I add the arrangement fee to my mortgage or pay it upfront?
Paying the arrangement fee upfront is usually cheaper because you avoid paying interest on it for the full mortgage term. However, if you are short of cash at completion, adding it to the loan is a reasonable option. On a £1,500 fee added to a 25-year mortgage at 4.5%, you would pay around £1,000 in additional interest over the term.
What is a mortgage overpayment and does it save money?
Yes, overpaying your mortgage reduces the outstanding balance faster, which cuts the total interest you pay. Most lenders allow overpayments of up to 10% of the outstanding balance per year without penalty. Overpaying by even £100 per month on a £200,000 mortgage at 4.5% can save thousands in interest and shorten the term by several years.
What is negative equity and why does it matter?
Negative equity means your outstanding mortgage balance is higher than the current value of your property. It can happen when house prices fall. If you are in negative equity, you may not be able to remortgage to a new deal, which means you could be stuck on your lender's SVR. Putting down a larger deposit reduces the risk of negative equity.
How do I compare mortgage deals fairly?
Use the total cost over the initial deal period as your main comparison: multiply monthly payments by the number of months, add all fees and subtract any cashback. Use the same method for every deal you are comparing. A mortgage broker or the Money Helper mortgage calculator at moneyhelper.org.uk can do this for you.
When should I use a mortgage broker?
A whole-of-market broker has access to deals from lenders who do not advertise directly to consumers, including specialist lenders for self-employed borrowers, those with adverse credit or unusual property types. If your situation is straightforward, comparison sites may be sufficient. If there is anything complicated about your income, property or credit history, a broker is worth the cost.