Remortgage Calculators

Remortgage calculator

If you already have a mortgage, remortgaging is often about making a better decision at the right time. For many homeowners, that can mean moving away from a higher rate, avoiding an expensive reversion, or reshaping the mortgage to better match current plans.

This remortgage calculator is designed to help you model “what if?” scenarios, so you can get a clearer sense of how your monthly payments might change before you compare specific options.

What this remortgage calculator estimates

This tool provides an illustrative estimate of how your monthly repayments could look based on the details you enter.

It’s particularly helpful for comparing common remortgage situations, such as:

• Switching to a new lender to access different rates and product features
• Moving from a fixed rate as your current deal ends
• Changing mortgage structure (for example, repayment vs interest-only, where applicable)
• Borrowing more as part of the remortgage (additional borrowing can affect both affordability and total cost)

What you can change in the calculator

Mortgage repayments are mainly influenced by:

1. Your mortgage balance (the amount you’re remortgaging)
2. The interest rate you’re assuming
3. The term (how long you’ll repay over)

Depending on the fields available in the calculator, you may be able to input items such as:

• Current property value (used to estimate your loan-to-value)
• Outstanding mortgage balance
• Remaining term (or the term you expect to take on)
• Current interest rate and new interest rate
• Mortgage type (repayment or interest-only, where relevant)

The calculator then uses your inputs to show an indicative view of:

• what your new monthly repayment could be under the scenario you choose
• your estimated new LTV

How to interpret the results

A calculator can’t replace a full mortgage assessment, because actual outcomes depend on lender criteria and the full cost of the deal.

However, the estimates are still useful because they help you:

• compare scenarios (for example, different rate assumptions)
• sense-check whether a remortgage is likely to reduce monthly payments
• understand how changing term or mortgage type may affect repayments
• identify which details matter most when you’re comparing options

A practical way to use the results is to treat them as a planning tool—a starting point for deciding what to explore further.

Why loan-to-value (LTV) matters

Your LTV is a key factor in how lenders price mortgages. It’s essentially the relationship between what you owe and the value of your property.

If your property value has increased or your balance has reduced, your LTV may improve. In many cases, that can broaden the range of options available.

If your LTV is higher, you may find fewer options or less favourable pricing.

The calculator’s LTV figure is based on the inputs you provide, so it’s best used to understand directionally how your position might change—not as a final valuation.

Costs to consider beyond the monthly payment

Monthly repayment is only one part of the remortgage picture. When comparing options, it’s important to factor in elements that can change the overall value of the deal, such as:

Early repayment charges (ERCs)

If you leave your current deal before it ends, you may face early repayment charges. These can be especially relevant if you’re early in a fixed-rate term.

Fees and setup costs

Remortgaging can involve costs such as:

• arrangement fees
• valuation fees
• legal and conveyancing costs
• broker fees (where applicable)

Some deals include incentives, so the “headline” monthly payment may not reflect the full cost.

Affordability and income at the time

Lenders reassess affordability when you remortgage. Your current income, outgoings, and any changes since you took out your original mortgage can affect what’s realistically available.

Remortgage basics (for context)

A remortgage is when you arrange a new mortgage on your property without necessarily moving home.

In practice, remortgaging often falls into one of two routes:

• Product transfer: switching to a new deal with your existing lender
• Switching lenders: moving your mortgage to a different lender

Which route is best can depend on the cost of leaving your current deal (including any ERCs), the options available, and how your circumstances have changed.

Using the calculator effectively

To get the most from your remortgage calculator results:

1. Start with a baseline using your current mortgage balance, remaining term, and current rate.
2. Model a range of new-rate scenarios to see how sensitive your repayments are.
3. Compare the estimated monthly change against likely costs, especially any ERCs and fees.
4. Review your LTV estimate to understand how your position may influence the options you can explore.

Related remortgage topics

If you want a wider overview of what can affect remortgage outcomes, the remortgage guides cover key decision points such as timing, ERCs, product transfers versus switching, and how LTV can influence rates.

• Things to consider about remortgaging
• Saving on your mortgage payments by remortgaging
• Remortgage FAQs