Mortgage Calculator
Estimate mortgage payments based on your inputs, with optional recurring tax, insurance, and HOA/service-charge assumptions.
Inputs
Result
Enter values on the left and select Calculate to see the result here.
What the Mortgage Calculator does
- Estimates the monthly principal-and-interest payment for a repayment mortgage based on the property price, deposit, annual interest rate, and term you enter.
- Shows the estimated mortgage balance, monthly principal and interest, optional monthly property tax, optional insurance, optional HOA/service charge, total monthly payment, total loan payments, and total interest.
- Helps you compare broad affordability scenarios before requesting lender quotes or reviewing a detailed Amortization Calculator schedule.
How to use the Mortgage Calculator
- Select the region and currency that best match the figures you want to enter.
- Enter the full property price and the deposit or down payment amount. The calculator estimates the loan amount as property price minus deposit.
- Enter the annual interest rate as a percentage and the repayment term in years. The term is converted into monthly payments.
- Enter optional annual property tax, annual home insurance, and monthly HOA/service charges only if you want those recurring costs included in the total monthly estimate; otherwise leave them at 0.
- Click Calculate and review the result as an estimate based on your inputs, not as a mortgage offer or affordability decision.
Formula / methodology used
- Loan amount = property price − down payment, floored at 0 if the down payment is greater than the property price.
- The annual interest rate is converted to a monthly rate: r = annual rate ÷ 12 ÷ 100, and the number of payments is n = loan term in years × 12.
- For interest-bearing repayment mortgages the calculator uses M = P × r × (1 + r)^n ÷ ((1 + r)^n − 1), where P is the mortgage balance.
- If the interest rate is 0%, the principal-and-interest payment is P ÷ n.
- Total loan payment = monthly principal-and-interest payment × n. Total interest paid = total loan payment − loan amount. Optional annual tax and insurance are divided by 12 and added with any monthly HOA/service charge to estimate total monthly cost.
Example calculation
A buyer estimates a £350,000 home purchase with a £70,000 deposit, a 4.75% annual rate, and a 25-year repayment term.
- Loan amount = £350,000 − £70,000 = £280,000
- Number of monthly payments = 25 × 12 = 300
- Monthly rate = 4.75 ÷ 12 ÷ 100 = 0.0039583
- Using the repayment formula, monthly principal and interest ≈ £1,596.33
- Total loan payments ≈ £1,596.33 × 300 = £478,898.58, so total interest ≈ £198,898.58 before optional costs
Result: The calculator would estimate about £1,596.33 per month for principal and interest. If you entered £0 for tax, insurance, and HOA/service charge, the total monthly payment estimate would also be about £1,596.33.
Common mistakes and limitations
- This is an estimate based on your inputs and is not a mortgage offer, approval, affordability assessment, or financial advice.
- It does not model arrangement fees, broker fees, insurance products, taxes not entered, legal fees, valuation fees, moving costs, early repayment charges, overpayments, product transfers, offset balances, or changes after an initial fixed/tracker period unless you explicitly include those costs in the inputs.
- Variable-rate changes, remortgaging, missed payments, daily interest, lender-specific rounding, and different payment dates can make real mortgage statements differ from this estimate.
- Do not enter the deposit as a percentage; the input expects a currency amount.
- The result depends heavily on the rate, term, deposit/loan amount, and repayment assumptions entered. Small rate changes can materially affect the payment and interest total.
Important note
This mortgage calculator provides a general estimate based on your inputs. It is not a mortgage offer, lender quote, affordability check, or financial advice. Confirm costs, fees, taxes, insurance, and eligibility with a regulated mortgage adviser or lender before making decisions.
Mortgage Calculator FAQs
Is this a mortgage offer or approval?
No. It is only an estimate based on your inputs. A lender may use credit checks, income checks, affordability rules, property valuation, fees, and product terms before offering a mortgage.
What affects the estimated monthly payment most?
The loan amount, annual interest rate, repayment term, and whether you add recurring costs such as property tax, insurance, or HOA/service charges.
Does it include arrangement fees, legal fees, valuation fees, or early repayment charges?
No. Those are not modelled unless you manually adjust your inputs. Budget separately for one-off fees and product-specific charges.
Does it handle variable rates or remortgaging?
No. The estimate assumes the entered rate and repayment pattern stay the same for the whole term. Recalculate with new assumptions if the rate or product changes.
When should I use the Amortization Calculator instead?
Use the Amortization Calculator when you want to see how each monthly payment is split between interest and principal over time.