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Mortgage Calculator

Calculate your monthly mortgage payments, total interest costs, and compare repayment versus interest-only options.

Mortgage type

Repayment

£180,000
£45,000
5.00% p.a.
25 years
£900/mo

LTV: 75.0% ✓ Good LTV for lending

Monthly payment

£789.20

Repayment over 25 years

Loan

£135,000

LTV

75.0%

Total interest

£101,759

Total repaid

£236,759

SDLT

£10,100

Gross yield

6.00%

BTL Stress Test

Lenders require rent ≥ 125% of mortgage payment at a 5.5% stress rate.

Min rent needed

£773/mo

Your rent

£900/mo

ICR coverage

1.45x

✓ Stress test likely to pass

Gross yield: 6.00% · Strong BTL return

Repayment vs Interest-Only

RepaymentInterest Only
Monthly payment£789.20£562.50
Total interest£101,759£168,750
Balance at end£0£135,000

IO reduces monthly cost but leaves the full loan outstanding at term end.

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Frequently Asked Questions

How much can I borrow for a mortgage?

Most UK lenders will lend 4-4.5 times your annual gross income. Some specialist lenders may go up to 5.5x. Use our Affordability Calculator for a more accurate estimate based on your income and outgoings.

What is the difference between repayment and interest-only mortgages?

With a repayment mortgage, your monthly payment covers both interest and capital, so the loan is fully repaid at the end of the term. With interest-only, you only pay the interest each month — the original loan amount remains and must be repaid at the end. Interest-only is popular with buy-to-let investors.

What deposit do I need for a mortgage?

Residential mortgages are available from 5% deposit (95% LTV), though 10-15% unlocks better rates. Buy-to-let mortgages typically require 25% minimum (75% LTV).

What is LTV and why does it matter?

LTV (Loan-to-Value) is the mortgage amount as a percentage of the property value. Lower LTV means better interest rates. For example, a 75% LTV mortgage on a £200,000 property means borrowing £150,000 with a £50,000 deposit.

Are mortgage calculator results accurate?

Our calculator uses the standard UK mortgage amortisation formula and produces accurate estimates. However, actual mortgage offers depend on your credit score, income verification, and individual lender criteria. Always consult a qualified mortgage broker for personalised advice.

Disclaimer: This calculator provides estimates for illustrative purposes only. Results are based on simplified assumptions and should not be relied upon for financial decisions. Actual costs, returns, and outcomes will vary. Always consult a qualified professional before making property or financial decisions.

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How the Mortgage Calculator Works

Our mortgage calculator uses the standard UK mortgage amortisation formula to provide accurate monthly payment estimates. For repayment mortgages, we calculate using the formula: M = P[r(1+r)^n]/[(1+r)^n-1], where P is the principal, r is the monthly interest rate, and n is the total number of payments.

Repayment vs Interest-Only

Repayment mortgages pay off both the interest and the capital over the term. At the end of your mortgage, you own the property outright. Monthly payments are higher but you build equity every month.

Interest-only mortgages only pay the interest each month. The original loan amount remains unchanged and must be repaid at the end of the term. Popular with buy-to-let investors as monthly costs are lower, maximising cash flow.

Understanding LTV

Loan-to-Value (LTV) is the percentage of the property price that you borrow. A lower LTV typically means better interest rates. Most residential lenders offer their best rates at 60% LTV, while buy-to-let mortgages commonly require a minimum 25% deposit (75% LTV).

Current UK Mortgage Rates

UK mortgage rates vary based on the Bank of England base rate, your LTV, credit score, and whether you choose a fixed or variable rate. Rates move with the base rate and repricing across the market, so any figure quoted here would date quickly. Compare current rates from multiple lenders, or use a whole-of-market mortgage broker.