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Free tool for UK landlords

Mortgage comparison calculator

Compare the true cost of different mortgage products side by side. Factor in every fee and any cashback to see which option is genuinely cheapest over the fixed term, not just which has the lowest headline rate.

Loan details

Affordability →
The repayment type applies to all options. Comparing interest only to capital repayment would not be a like for like comparison.

1 Option 1

2 Option 2

Results

Enter loan amount and interest rates for at least two options to see comparison
Important: This calculator provides estimates only and is not financial advice. Actual mortgage costs may vary. Interest is calculated on a simple annual basis for comparison purposes. Verify the actual costs with your lender or mortgage broker before making any decisions.

Understanding mortgage costs

Why the lowest rate isn't always the cheapest

The cheapest mortgage is not always the one with the lowest rate. Product fees, broker and legal costs, and any cashback all change the total, so two deals with similar rates can cost very different amounts once everything is added up. Take a £200,000 loan fixed for 5 years: a 4.5% rate with a £999 fee can end up dearer or cheaper than a 4.8% rate with no fee, depending on the numbers. This calculator settles it by comparing the true cost over the fixed term, not the headline rate.

If you are weighing this up at the end of a deal, the remortgage and ERC calculator also checks whether switching early beats the early repayment charge.

What this calculator works out

For each option it shows the total interest over the fixed term, the total fees once cashback is taken off, a simplified effective annual rate, and the cost per month, then totals them into a single cost over the term and flags the cheapest.

Keep the comparison like for like: use the same fixed term and the same repayment type for every option, since an interest only deal and a repayment deal are not directly comparable. Early repayment charges are not included here, as they depend on when you leave the deal.

Common questions about comparing mortgages

Is the lowest mortgage rate always the cheapest option?

No. A lower rate that carries a big product fee can cost more overall than a slightly higher rate with no fee. What matters is the total cost over the fixed term with every fee included, which is what this calculator works out.

Is it worth paying a product fee for a lower rate?

It depends mostly on the loan size and how long you fix for. On a larger loan the saving from a lower rate is bigger, so a fee is more often worth paying; on a smaller loan the fee can wipe out the saving. A longer fix also gives the lower rate more time to earn back the fee. The only way to be sure is to compare the total cost both ways, which is what this tool is for.

What is a typical mortgage product or arrangement fee?

On residential deals a fixed product fee is often somewhere around £999 to £1,500, though it varies by lender. On buy to let, fees are frequently charged as a percentage of the loan instead, and can run from nothing up to several percent on specialist products, so on a large loan a percentage fee can be a lot more than a flat one. Always check whether the fee is a flat amount or a percentage before comparing.

What fees should I include when comparing mortgages?

Include the product or arrangement fee, plus broker, solicitor, application, valuation, exit and CHAPS fees, and take off any cashback. The small ones are easy to skip but they add up, and leaving them out flatters whichever deal hides more cost in fees.

Should I add the product fee to my loan or pay it upfront?

Paying upfront costs less overall because you avoid paying interest on the fee, but you need the cash at the start. Adding it to the loan keeps your cash free but means interest on the fee for the whole term, and on a remortgage it also nudges up your loan to value, which can be a problem if the property has not gained value. Compare both ways here to see the gap.

What is the effective annual rate?

It is the total cost of the deal, fees included, expressed as a yearly percentage of the loan. It is a fairer way to compare two products than the headline rate alone, because it folds the fees back into a single rate you can read at a glance. The figure here is a simplified guide rather than the formal APRC a lender quotes.