Mortgage Comparison Calculator

When it comes to choosing which type of mortgage is the best for you, it can be fairly complicated. Whether you are weighing up different repayment types, deal terms, interest rate types, or even exploring more specialist products, you’ll usually want to see a side by side comparison.

The good news is, our comprehensive comparison calculator does just that. Read on to find out more about how it works, and what to do when you’ve narrowed down your choices.

How to use the calculator

This mortgage comparison calculator can be used to work out your monthly payments and overall costs across a wide variety of mortgage structures, from standard capital repayment and interest-only to part-and-part and offset deals.

Enter the following details to get started

Select the aspect of the mortgage deal you want to compare on the radio button. You can choose from:

• Repayment Type

• Interest Rate Type

• Mortgage Type

• Mortgage Purpose

Once you’ve selected this, the calculator will default to your chosen functionality.

You’ll then need to enter:

• The property value

• Your deposit amount

• The interest rates of the 2 products you’re comparing

To get the most useful results, it’s best to compare one aspect of the deal at a time, so unless you are comparing interest rate types, it’s recommended to use the same interest rate figure for both Deal A and B, where possible

• The term length

• You then choose from the drop down list whichever elements are relevant to your particular calculation - For example, if you’ve chosen to compare repayments types, you would choose interest-only as Deal A and part and part as type B, or repayment as Deal A and interest-only as Deal B etc

How this calculator works

Our mortgage comparison calculator takes the amount you have entered and works out how much the monthly repayments and total interest payable will be on a mortgage of that size when split over the term length you choose.

What sets this tool apart is its ability to simultaneously calculate and compare results for 2 different deals at the same time, allowing you to make a side by side comparison.

Depending on the mortgage type you select, the calculator adapts its formulas:

• For Repayment & Interest-Only: It runs a side-by-side analysis showing how your mortgage debt will progressively decrease over time with a capital repayment mortgage, compared to an interest-only mortgage where the capital debt remains unchanged

• For Part-and-Part (Hybrid): It takes your total loan requirement and splits the calculation. It applies standard amortisation to the repayment portion while calculating simple interest on the remaining interest-only portion, combining them into one clear monthly payment figure

• For Offset Mortgages: By entering your projected savings balance, the calculator offsets this against your mortgage debt, showing you exactly how much you could save in interest and how it impacts your monthly outgoings

• For Green mortgages: Some lenders offer a small rate discount (typically 0.1%) for energy-efficient properties, it provides results based on this principle

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What types of mortgages can it compare?

Because this tool uses advanced functionality, our mortgage comparison calculator works for almost all types of mortgage, including:

• First-time buyer mortgages
• Part-and-part mortgages (which combine capital repayment and interest-only)
• Interest-only mortgages
• Offset mortgages
• Green mortgages (which often offer discounts or additional borrowing for those with energy efficient homes)
• Buy-to-let mortgages

Example Calculations

Below we’ve provided a couple of tables which show how the calculator can be used to help you make an informed comparison between mortgage types. However, it’s always a good idea to speak with a broker if you’re unsure why one mortgage is more suitable for you than the next:

Comparing repayment types

Capital repayment vs interest-only repayment deals are one of most common comparisons borrowers make. This can often be the biggest difference in monthly repayments, but it’s important to understand all of the factors that differ between these two mortgage types.

In this scenario, we are looking at a borrower who wants to take out a £200,000 mortgage over a 25-year term with an interest rate of 4.5%.

While the interest-only mortgage saves the borrower roughly £361 a month, the overall cost is significantly higher because the principal loan amount is never reduced, meaning interest is charged on the full £200,000 for the entire 25 years.

Comparing different mortgage product types

It can be much more complex when you’re comparing two completely different products, as the benefits and drawbacks typically go way beyond how much you spend or save over time.

In this example we look at a borrower who wants to compare a part and part repayment mortgage with using an offset mortgage account with £50k of savings available. They take out a £250,000 mortgage over a 25-year term at an interest rate of 5.0%:

What to do after running your calculations

Once you’ve had a chance to look over a variety of scenarios and have a better idea of which mortgage structure suits your financial situation, reach out to one of our brokers.

We will compare the latest mortgage rates from across the market for you and offer bespoke advice on which is the best suited to your needs. We can target purely those mortgage types that you’ve considered through your comparisons above, or recommend other deal types that may be more beneficial to your circumstances.

Ready to get your rates comparison and speak to a broker about your options? Get started here.