FinToolSuite

Remortgage Savings Calculator

Updated April 17, 2026 · Mortgage · Educational use only ·

Savings from remortgaging to a lower rate.

Calculate savings from remortgaging to a lower rate after accounting for switching costs. Enter monthly payment and new monthly payment to see net savings.

What this tool does

Enter current and new monthly payments, switching costs, and fix period. The tool shows net savings.


Enter Values

Formula Used
Current monthly
New monthly
Fix period
Upfront costs

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Calculations, display, or translation — let us know.

Disclaimer

Results are estimates for educational purposes only. They do not constitute financial advice. Consult a qualified professional before making financial decisions.

Dropping from 6% to 4.5% on a 200,000 mortgage saves about 180/month. Over a 2-year fix that's 4,320 before switching costs. Typical switching costs 1,500 (ERC if applicable plus new arrangement fee) leaves 2,820 net savings. Worth doing. Higher fees or shorter fix periods can flip the answer.

A worked example

Try the defaults: current monthly payment of 1,289, new monthly payment of 1,109, switching costs of 1,500, new fix period of 24. The tool returns 2,820.00. You can adjust any input and the result updates as you type — no submit button, no reload. That's the real power here: seeing how sensitive the output is to one or two assumptions.

What moves the number most

The result responds to Current Monthly Payment, New Monthly Payment, Switching Costs, and New Fix Period. Not every input has equal weight. Flip one at a time toward extreme values to feel which ones move the needle most for your situation.

The formula behind this

Monthly gap × months minus switching costs. Everything the calculator does is shown in the formula box below, so you can check the math against your own spreadsheet if you want.

Stress-testing the plan

Run the calculation at your current rate, then run it again at a rate 2–3 percentage points higher. That's roughly what a product reset could bring at renewal, and it's a useful check on whether you can afford the mortgage in a higher-rate world, not just today's.

What this doesn't capture

The figure excludes arrangement fees, valuation costs, legal fees, insurance, and any early-repayment charges — those can add several thousand to the headline cost. Rate changes at renewal for fixed-term deals will shift the picture further. Use this for the core interest/principal math and add the other costs on top.

Example Scenario

Remortgage savings produces a net figure based on the inputs provided.

Inputs

Current Monthly Payment:1,289 £
New Monthly Payment:1,109 £
Switching Costs:1,500 £
New Fix Period:24 months
Expected Result£2,820.00

This example uses typical values for illustration. Adjust the inputs above to match a specific situation and see how the result changes.

Sources & Methodology

Methodology

Monthly gap × months minus switching costs.

Frequently Asked Questions

Break-even months?
Switching costs divided by monthly saving. 1,500 / 180 = 8.3 months break-even. Anything shorter means you lose money on the switch.
What counts as switching cost?
Early-repayment charge on current mortgage, new arrangement fee, broker fee, legal/valuation costs. Sum all before deciding.
Is the saving really this simple?
Close to it. Small differences exist because mortgages amortise at different rates under different payments, but the payment-gap approximation is accurate enough for decision-making.
Fee-free remortgage?
Some lenders offer fee-free products. Rate is usually slightly higher than low-fee versions. Compare total cost across the fix.

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