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Smarter mortgage and ISA planning tools with practical guides to help users make clearer decisions.

Disclaimer: NestBoost provides educational projections and planning estimates only. Results depend on assumptions you provide and may differ from actual outcomes due to market movement, rate changes, fees, product rules, tax treatment, and personal circumstances. Content is not regulated financial advice or a recommendation to buy, sell, borrow, or invest. Always verify details with your provider and consider speaking to a qualified professional before making financial decisions.

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Mortgage Calculator

Mortgage Calculator FAQs

Short answers to the common questions people ask before using the tool.

It gives you a quick estimate of deposit amount, loan size, monthly payment, and total repayment based on the property price, deposit, rate, term, and mortgage type you choose.

No. This is a planning tool. A lender will also look at income, spending, credit profile, and stress-tested affordability before deciding how much it is prepared to lend.

Use repayment if you want to model the most common residential mortgage structure. Interest-only is mainly useful if you want to compare the lower monthly payment against the fact that the capital still has to be repaid later.

Yes. Even a modest rate change or a longer term can noticeably change both the monthly payment and the total interest paid, which is why it helps to test a few versions before treating one result as fixed.

Open the advanced mortgage calculator when you want richer comparison tools, fee handling, premium charts, and deeper decision support beyond this quick estimate. Open advanced calculator. Sign in for extras like scenario management and report workflows.

What This Calculator Shows

This calculator is useful when you already have a rough property budget in mind and want to see what that means for the deposit, mortgage size, and monthly repayment.

It also helps you compare whether a bigger deposit, lower purchase price, longer term, or different mortgage type changes the numbers enough to make the plan feel more comfortable.

Worked Example

One simple scenario to show how the inputs translate into a mortgage estimate.

Example scenario

Property

£250,000

Deposit

10% (£25,000)

Mortgage

£225,000

Rate

4.5%

Term

25 years

Type

repayment

In a case like this, a small change in rate or term can shift the monthly payment enough to change whether the purchase still feels realistic. It is usually worth testing a few nearby versions rather than relying on the first result.

Related Guides and Articles

Useful next reads if you want more context around affordability, deposits, and how the numbers change.

  • Mortgage
    How Much Mortgage Can I Afford in the UK?
  • Mortgage
    95% vs 90% vs 85% LTV: What Deposit Level Actually Changes
  • Mortgage
    First-Time Buyer's Guide to Getting a Mortgage in the UK