# mortgagecalculator.siten.co

> Independent mortgage guides — 15 in this language — plus a browser-side mortgage calculator for twelve markets, each with its own currency, rate convention, deposit expectation and purchase taxes.

Contact: hello@mortgagecalculator.siten.co
Languages: en (https://mortgagecalculator.siten.co/), de (https://mortgagecalculator.siten.co/de), es (https://mortgagecalculator.siten.co/es), fr (https://mortgagecalculator.siten.co/fr), hi (https://mortgagecalculator.siten.co/hi), id (https://mortgagecalculator.siten.co/id), it (https://mortgagecalculator.siten.co/it), nl (https://mortgagecalculator.siten.co/nl), pl (https://mortgagecalculator.siten.co/pl), pt (https://mortgagecalculator.siten.co/pt), sv (https://mortgagecalculator.siten.co/sv), tr (https://mortgagecalculator.siten.co/tr)

## Guides (https://mortgagecalculator.siten.co/guides)

- [How Long Should a Mortgage Be? The Term Trade-Off](https://mortgagecalculator.siten.co/guides/choosing-a-mortgage-term-length): A longer term lowers the payment and raises the total sharply. Here is what each extra decade actually costs, and why flexibility usually beats commitment. — Refinancing and overpaying, Updated 2026-08-09.
- [Overpaying Your Mortgage: What It Actually Saves](https://mortgagecalculator.siten.co/guides/overpaying-your-mortgage): A modest regular overpayment can remove years from the term and a large share of the interest — provided it reduces the term rather than the payment. — Refinancing and overpaying, Updated 2026-08-09.
- [When Refinancing Is Worth It: The Break-Even Calculation](https://mortgagecalculator.siten.co/guides/when-to-refinance-a-mortgage): Refinancing pays when the monthly saving clears the total cost of switching before you leave. Here is the sum, and the four cases where it fails. — Refinancing and overpaying, Updated 2026-08-08.
- [First-Time Buyer Mortgages: The Schemes, and the Catches](https://mortgagecalculator.siten.co/guides/first-time-buyer-mortgages): Low-deposit products, state guarantees and shared ownership all reduce the cash you need — and each of them costs something. Here is what. — Mortgage types, Updated 2026-08-08.
- [Mortgages Around the World: Why Advice Does Not Translate](https://mortgagecalculator.siten.co/guides/mortgage-types-by-country): A thirty-year fix, a five-year fix and a lifetime tracker are all called fixed-rate mortgages somewhere. Here is what actually differs between markets. — Mortgage types, Updated 2026-08-08.
- [Repayment or Interest-Only? What You Owe at the End](https://mortgagecalculator.siten.co/guides/repayment-vs-interest-only-mortgage): One clears the debt over the term; the other leaves the whole balance outstanding at the end. Here is who interest-only is actually for. — Mortgage types, Updated 2026-08-07.
- [Debt to Income: The Ratio That Decides More Applications Than Salary](https://mortgagecalculator.siten.co/guides/debt-to-income-ratio-explained): How DTI is calculated, what counts as debt, the caps that apply in different markets, and the fastest ways to move the ratio before applying. — Affordability and deposit, Updated 2026-08-07.
- [Deposit and LTV: Why the Bands Matter More Than the Amount](https://mortgagecalculator.siten.co/guides/deposit-and-loan-to-value-explained): Rates are priced in LTV bands, so a small extra deposit that crosses a threshold can be worth more than any negotiation. Here is where the thresholds sit. — Affordability and deposit, Updated 2026-08-07.
- [How Much Can I Borrow? What the Lender Is Actually Calculating](https://mortgagecalculator.siten.co/guides/how-much-can-i-borrow): Income multiples are the rule of thumb; debt-to-income, the stress test and your outgoings are what really set the number. Here is the whole calculation. — Affordability and deposit, Updated 2026-08-06.
- [How Mortgage Interest Is Calculated, Month by Month](https://mortgagecalculator.siten.co/guides/how-mortgage-interest-is-calculated): Interest is charged on what you still owe, not on what you borrowed. That one sentence explains amortisation, overpayment savings and daily interest. — Rates and costs, Updated 2026-08-06.
- [APR and Fees: Why the Cheapest Rate Is Often the Expensive Deal](https://mortgagecalculator.siten.co/guides/mortgage-apr-and-fees-explained): A large arrangement fee can turn the best headline rate into the worst offer. Here is how APR works, what it misses, and how to compare properly. — Rates and costs, Updated 2026-08-06.
- [Fixed or Variable? The Decision Is About Your Budget, Not the Market](https://mortgagecalculator.siten.co/guides/fixed-vs-variable-mortgage-rates): Fixed buys certainty and costs a little more; variable starts lower and moves. The honest test is what a three-point rise would do to you. — Rates and costs, Updated 2026-08-05.
- [Mortgage Terms Explained: The Words on Every Offer](https://mortgagecalculator.siten.co/guides/mortgage-terms-glossary): APR, LTV, DTI, amortisation, early repayment charge, porting — the vocabulary you need before comparing two offers, with what each one actually costs you. — Mortgage basics, Updated 2026-08-05.
- [How a Mortgage Actually Works, Start to Finish](https://mortgagecalculator.siten.co/guides/how-a-mortgage-works): What you are agreeing to when you take a mortgage: the security, the stages of the process, and the points where the deal can still change. — Mortgage basics, Updated 2026-08-04.
- [How a Mortgage Calculator Works: The Formula, Shown](https://mortgagecalculator.siten.co/guides/how-a-mortgage-calculator-works): One equation produces the monthly payment, and everything else follows from running it month by month. Here is the arithmetic, and what most calculators leave out. — Mortgage basics, Updated 2026-08-04.

## Topics (https://mortgagecalculator.siten.co/topics)

- [Mortgage basics](https://mortgagecalculator.siten.co/topics/mortgage-basics): How a mortgage actually works, what the calculator is doing behind the monthly figure, and the vocabulary you need before comparing two offers. — 3 guides.
- [Rates and costs](https://mortgagecalculator.siten.co/topics/rates-costs): Fixed against variable, what APR includes that the headline rate does not, and how interest is calculated month by month on a falling balance. — 3 guides.
- [Affordability and deposit](https://mortgagecalculator.siten.co/topics/affordability): How much you can borrow and why lenders arrive at that figure: income multiples, debt-to-income, stress tests, deposit size and the LTV bands that set your rate. — 3 guides.
- [Mortgage types](https://mortgagecalculator.siten.co/topics/mortgage-types): Repayment against interest-only, the products that only exist in certain countries, and the schemes aimed at first-time buyers. — 3 guides.
- [Refinancing and overpaying](https://mortgagecalculator.siten.co/topics/refinancing): What happens after completion: when refinancing is worth the fees, what overpaying really saves, and how the term length changes both the payment and the total. — 3 guides.

## Mortgage calculators by country (https://mortgagecalculator.siten.co/calculator)

- [the United States](https://mortgagecalculator.siten.co/calculator/united-states): Thirty-year fixed rates are the default here and exist almost nowhere else, closing costs are itemised in detail, and mortgage insurance is added whenever the deposit is under a fifth of the price.
- [the United Kingdom](https://mortgagecalculator.siten.co/calculator/united-kingdom): Short fixed periods of two to five years sitting on a much longer term, arrangement fees that can be added to the loan, and stamp duty as the largest single upfront line.
- [Germany](https://mortgagecalculator.siten.co/calculator/germany): Long fixed periods and a large deposit expectation, with purchase costs — transfer tax, notary, land registry and agent commission — that routinely add a tenth to the price.
- [France](https://mortgagecalculator.siten.co/calculator/france): Almost entirely fixed-rate lending with a hard limit on the share of income that can go to debt, borrower insurance priced into the offer, and notary fees that dominate the upfront cost.
- [Spain](https://mortgagecalculator.siten.co/calculator/spain): A market that moved from variable to fixed over the last decade, with transfer tax set regionally and a deposit expectation that is higher for non-residents.
- [Italy](https://mortgagecalculator.siten.co/calculator/italy): Fixed and variable side by side, notary costs that are substantial and non-negotiable, and tax treatment that changes sharply depending on whether the property is your main home.
- [the Netherlands](https://mortgagecalculator.siten.co/calculator/netherlands): The longest fixed periods in Europe, the possibility of borrowing the full purchase price, and mortgage interest relief that makes the net cost lower than the gross payment suggests.
- [Poland](https://mortgagecalculator.siten.co/calculator/poland): Rates that move with the reference rate and a market historically dominated by variable pricing, alongside periodic state schemes aimed at first-time buyers.
- [Portugal](https://mortgagecalculator.siten.co/calculator/portugal): Long terms, variable rates tied to Euribor with fixed options alongside, and a purchase tax that scales steeply with the price of the property.
- [Sweden](https://mortgagecalculator.siten.co/calculator/sweden): Very long terms with short rate-fixing periods, plus a mandatory amortisation requirement that rises with the loan-to-value ratio and changes the monthly figure directly.
- [India](https://mortgagecalculator.siten.co/calculator/india): Floating rates linked to an external benchmark, stamp duty set state by state and often the largest upfront cost, and terms that shorten with the borrower’s age.
- [Türkiye](https://mortgagecalculator.siten.co/calculator/turkey): Rates are quoted monthly rather than annually here, terms are short by international standards, and the title deed fee is the dominant purchase cost.

## Frequently asked questions

### How does a mortgage calculator work?
It solves one equation. For a standard repayment loan the monthly payment is the amount borrowed multiplied by the monthly interest rate, divided by one minus (one plus the monthly rate) raised to minus the number of months. That single formula produces a payment which, repeated for the whole term, clears the debt exactly. Everything else a good calculator shows — total interest, the balance after five years, how much of the first payment is interest — comes from running that payment through the balance month by month. Ours also adds the purchase costs, because those decide whether you can complete at all.

### Why is my mortgage calculation different from the bank’s?
Usually for one of four reasons. The bank is quoting APR rather than the nominal rate, so its figure includes fees. It is adding compulsory insurance to the payment. It is using a slightly different day-count or rounding convention. Or the rate it has offered you is not the one you typed in, because your deposit, income or credit history put you in a different band. A calculator gives you the shape of the deal; only a lender’s illustration gives you the deal.

### How much deposit do I need?
It depends entirely on the market, which is why this site has a page per country. Around a fifth of the price is the common expectation in Germany, Spain and Italy, and it also removes mortgage insurance in the United States. Ten per cent is workable in the United Kingdom and Portugal. The Netherlands still allows borrowing the full purchase price. But there is a second question that matters as much: purchase taxes and fees are almost never lendable, so in a market where they run to a tenth of the price you need that in cash on top of the deposit.

### Should I take a fixed or a variable rate?
It is a question about your budget rather than about forecasting rates. A fixed rate buys certainty and normally costs slightly more at the outset; a variable rate starts lower and moves. The honest test is what happens to you if the payment rises by two or three percentage points: if that would be uncomfortable rather than merely annoying, the certainty is worth paying for. Note that the two words mean different things by country — a British five-year fix is a short window inside a long term, while a French or Dutch fix can run the whole way.

### Is it better to shorten the term or to overpay?
They achieve almost the same thing with a very different risk profile. A shorter term forces higher payments and locks you into them. Overpaying a longer-term loan produces nearly the same saving while leaving you the option of stopping in a difficult month. For most people the flexible version is the better arrangement, provided you actually make the overpayments. Two things to check first: whether your lender charges an early repayment fee, and whether the overpayment reduces the term or the monthly payment, because the saving is much larger when it reduces the term.

### Does this calculator store what I type?
No. The whole calculation runs in your browser using JavaScript on the page. The price, deposit, rate and term you enter are never sent to a server, never logged and never stored, because there is no request to send them in — there is no reason for arithmetic to leave your device, and refusing to collect the data is the only privacy promise that cannot be broken later.