Mortgage calculator
Enter the price, down payment, rate and term to estimate your monthly mortgage payment.
Free mortgage calculator with taxes, insurance and amortization
This mortgage calculator estimates your monthly mortgage payment from the home price, your down payment, the interest rate and the loan term. It also adds optional property tax and home insurance to show the full monthly cost, works out the total interest you will pay over the life of the loan, and draws an amortization chart so you can see how the balance falls over time. Everything is calculated instantly in your browser; nothing is sent to a server.
How a mortgage payment is calculated
A standard repayment mortgage uses the amortizing loan formula. Your fixed monthly payment for principal and interest is:
Where M is the monthly payment, P is the loan amount (home price minus down payment), r is the monthly interest rate (the annual rate divided by 12 and by 100), and n is the number of monthly payments (years × 12). Because the rate is applied to the balance that is still outstanding, the payment stays constant but the split between interest and principal changes every month.
What amortization means
Amortization is the process of paying off a loan with regular equal payments. At the start, most of each payment goes to interest because the outstanding balance is large; only a small part reduces the principal. As the balance shrinks, the interest portion falls and more of every payment chips away at the principal. That is why the amortization curve above is steep near the end: the loan is repaid faster in its final years. It also explains why overpaying early in the loan saves a disproportionate amount of interest.
Principal, interest, taxes and insurance (PITI)
Lenders often talk about PITI, the four parts of a typical housing payment:
- Principal — the part of the payment that repays the amount you borrowed.
- Interest — the lender's charge for lending the money, based on the rate and the remaining balance.
- Taxes — annual property tax (council tax band, IBI, IMI, taxe foncière depending on the country), usually collected monthly.
- Insurance — buildings or home insurance, and sometimes mortgage protection insurance.
This calculator lets you add the annual tax and insurance so the "total monthly payment" reflects what really leaves your account each month, not just principal and interest.
Fixed rate vs variable (adjustable) rate
A fixed-rate mortgage keeps the same interest rate for a set period, so your payment is predictable. A variable or adjustable-rate mortgage moves with a reference index (such as the central bank rate or Euribor), so payments can rise or fall. Fixed rates give certainty and protect you if rates climb; variable rates can be cheaper when rates are low or falling but carry the risk of higher payments later. This tool models a fixed rate; to test a variable scenario, recalculate with the higher rate you want to stress-test.
Nominal rate vs APR (and TIN vs TAE)
The nominal rate (called TIN in Spain, taux nominal in France) is the pure interest used in the payment formula. The APR (TAE in Spain, TAEG in France) is a broader figure that also includes fees, compulsory insurance and other costs, so it is the fairer number for comparing offers. Two mortgages can share the same nominal rate but have very different APRs once fees are included. Always compare lenders on APR, not just the headline rate.
Down payment, LTV and mortgage insurance
Your down payment is the cash you put in up front; the rest is the loan. The loan-to-value (LTV) ratio is the loan divided by the property price. A bigger down payment means a lower LTV, which usually unlocks better interest rates and avoids extra costs. In several markets, borrowing above roughly 80% LTV triggers private mortgage insurance (PMI) or a higher rate, because the loan is riskier for the lender. Increasing your down payment is one of the most effective ways to cut both your monthly payment and the total interest.
Loan term: 15, 25 or 30 years
A longer term lowers the monthly payment but increases the total interest, because you borrow the money for longer. A shorter term does the opposite: higher monthly payments but far less interest overall. For example, the same loan over 15 years instead of 30 can save a large share of the lifetime interest while raising the monthly payment. Use the years and months fields to compare terms and find a payment you can comfortably afford.
How to pay less interest on your mortgage
- Make a larger down payment to borrow less and lower your LTV.
- Choose a shorter term if the higher monthly payment fits your budget.
- Overpay when you can — extra payments early on remove interest for the whole remaining term.
- Shop on APR and refinance if rates fall significantly and the fees are worth it.
A worked example
Suppose you buy a £250,000 home with a £50,000 down payment, so you borrow £200,000 at a 4% fixed annual rate over 25 years (300 monthly payments). The monthly rate is 4% ÷ 12 = 0.333%. The formula gives a monthly principal-and-interest payment of about £1,056. Over the full term you repay roughly £316,700, of which about £116,700 is interest — more than half of the original loan again. Raise the deposit to £80,000 (20%) and the loan drops to £170,000 with a payment near £897; shorten the term to 20 years and the payment rises but you remove tens of thousands in interest. Small input changes move the lifetime cost a lot.
What an amortization schedule looks like
An amortization schedule lists every payment and how it splits between interest and principal. For the £200,000 loan above, the first month is very different from the last:
| Month | Payment | Interest | Principal | Balance |
|---|---|---|---|---|
| 1 | £1,056 | £667 | £389 | £199,611 |
| 60 | £1,056 | £607 | £449 | £181,500 |
| 150 | £1,056 | £430 | £626 | £128,500 |
| 300 | £1,056 | £4 | £1,052 | £0 |
Early on, about two thirds of the payment is interest; by the final payment almost all of it is principal. That is why the balance barely moves in the first years and then falls quickly.
Repayment vs interest-only mortgages
A repayment (capital and interest) mortgage — what this calculator models — clears the whole debt by the end of the term. An interest-only mortgage has lower monthly payments because you pay only the interest, but the full loan is still owed at the end and must be repaid from savings, a sale or another plan. Interest-only costs far more over time and is now restricted for most residential buyers; repayment is the safe default for a home you live in.
Costs beyond the mortgage
The monthly payment is not the only cost of buying. Budget for one-off purchase costs, which vary by country but usually include a property transfer tax or stamp duty (Stamp Duty in the UK, ITP/AJD in Spain, droits de mutation in France, IMT and Imposto do Selo in Portugal), notary and land-registry fees, a lender valuation, and possible broker or arrangement fees. Together these can add several percent of the price on top of your deposit, so include them when working out how much cash you really need.
Remortgaging or switching lender
You are not locked in forever. Remortgaging (subrogación in Spain, transferência de crédito in Portugal) moves the loan to a better deal, usually a lower rate or different term. It can save money when market rates fall or your fixed period ends, but weigh the new fees, early-repayment charges and valuation costs against the saving. Re-run this calculator with the new rate and your remaining balance to see whether switching actually pays off.
How much can you borrow?
Lenders cap the loan based on your income and existing debts. A common guideline is that total housing costs stay around 30–35% of net income, and most lenders apply a stress test to check you could still pay if rates rose by a few points. Borrowing the maximum offered is rarely wise — leave room for rate rises, maintenance and life. When checking affordability, use the total monthly payment from this tool, including tax and insurance, not just principal and interest.
Frequently asked questions
Does this calculator include taxes and insurance? Yes, the annual property tax and home insurance fields are optional; leave them at zero for principal and interest only.
Is the result exact? It is an accurate estimate using the standard amortization formula. Your real offer may differ slightly due to fees, rounding, insurance and the lender's exact method.
What interest rate should I use? Use the rate a lender quotes you, or a current market average for your country and term to get a realistic estimate.
Can I model overpayments? Indirectly: lower the term or the loan amount to see how paying down faster reduces total interest.