Mortgage Calculator
Work out what a mortgage really costs each month — not just the loan repayment, but property tax, insurance and service charges too, plus what overpaying would save you.
Fill in the fields to see your result.
Year-by-year breakdown
How the balance falls over the life of the loan, and how much of each year goes on interest.
What's actually in a mortgage payment
The number a lender advertises is usually just the loan repayment. What actually leaves your account each month is normally four things stacked together:
- Principal — the part that reduces what you owe.
- Interest — the lender's charge for the money.
- Property tax — council tax, municipal tax, or whatever your country calls it.
- Insurance — buildings cover, which lenders normally require.
Add a service charge or HOA fee if you're buying an apartment or on a managed estate. In the US these four are known together as PITI. Budgeting from the loan repayment alone is the single most common way people underestimate what a house costs them.
The formula
The loan part uses the standard amortisation formula:
Property tax, insurance and any service charge are simply divided by twelve and added on top.
A worked example
A 350,000 property with a 20% deposit, at 6.5% over 30 years:
- Deposit: 70,000 — so the mortgage is 280,000
- Principal & interest: about 1,770 a month
- Property tax at 1.1% of the price: about 320 a month
- Insurance at 1,800 a year: 150 a month
- Total: roughly 2,240 a month — around 470 more than the loan payment alone
Over the full 30 years, that mortgage costs about 357,000 in interest — more than the amount borrowed. Which is why the next section matters.
Why overpaying is so powerful on a mortgage
Mortgages run for decades, and interest compounds over every one of those months. An extra payment made early doesn't just reduce the balance once — it stops interest being charged on that money for the remaining twenty-something years.
Put a modest figure in the "extra payment" box above and watch two numbers: the interest saved, and the years knocked off the term. On a typical 30-year mortgage, an overpayment of a couple of hundred a month often saves five to seven years and a six-figure sum in interest.
Two things to check first: whether your lender charges an early-repayment penalty, and whether overpayments are applied to the balance rather than held against future payments. Both are in your mortgage offer.
How big a deposit do you need?
| Deposit | What it usually means |
|---|---|
| Under 10% | Fewer lenders, higher rates, and mortgage insurance almost everywhere |
| 10–19% | Workable, but you'll often still pay mortgage insurance |
| 20% or more | The usual threshold for dropping mortgage insurance and getting better rates |
| 40%+ | Typically the best rates on offer |
The badge above your result tells you which band you're in. Note that this calculator does not add mortgage insurance (PMI in the US) to your monthly figure — if your deposit is under 20%, budget for it separately and ask your lender what it would cost.
Costs this calculator doesn't include
Buying a home comes with one-off costs that don't show up in a monthly payment: legal fees, survey or valuation, stamp duty or transfer tax, mortgage arrangement fees, moving costs. Depending on where you are, these can add several percent of the purchase price. And once you own it, maintenance is real — a common rule of thumb is to set aside around 1% of the property's value a year for repairs.
Frequently asked questions
Is this calculator accurate for my country?
The loan maths is universal, and it's the same formula lenders use everywhere. What varies is the extras: property tax rates, whether insurance is compulsory, and what local taxes apply on purchase. Because you type in your own tax and insurance figures, the result adapts to wherever you are — just make sure those inputs reflect your local rates.
Does it include mortgage insurance or PMI?
No. If your deposit is under about 20%, most lenders add mortgage insurance, which typically runs somewhere around 0.3% to 1.5% of the loan a year. Ask your lender for the exact figure and add it to the monthly total you see here.
Should I take a 15-year or a 30-year mortgage?
A 30-year term gives you a lower monthly payment; a 15-year term costs far less in total interest, often less than half. Run both in the calculator and compare the 'total interest' line. The honest answer depends on whether the higher payment would leave you without a safety margin — a term you can comfortably afford, plus voluntary overpayments, is usually safer than committing to a short one.
What is escrow?
In some countries, notably the US, the lender collects your property tax and insurance alongside the loan payment and holds it in an escrow account, then pays those bills for you. That's why your monthly figure there includes all of it. Elsewhere you may pay those bills yourself — the total cost is the same either way, which is why this calculator shows them together.
Why does so little of my early payment reduce the balance?
Interest is charged on what you still owe, and in year one you owe almost the whole amount. On a 30-year mortgage the early years are mostly interest, and the crossover — where more of your payment goes to principal than to interest — often doesn't arrive until somewhere in the second decade. The year-by-year table on this page shows exactly when it happens for your numbers.
Are my figures sent anywhere?
No. Everything is calculated inside your own browser. Nothing you type is uploaded, stored or shared, and there's no sign-up.
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Please note: CalcuLane gives estimates for general information only and is not financial advice. Lenders round differently, and fees, insurance and payment-date rules can change what you actually pay. Always confirm figures with your lender before committing to a loan.