Mortgage Calculator
Calculate your exact monthly mortgage payment and total cost over the full term. See how much goes to interest vs capital, and how overpayments could save you thousands.
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Mortgage Guide
Repayment vs Interest Only
A repayment mortgage reduces your loan balance every month — by the end of the term, you own the property outright. An interest-only mortgage keeps payments lower but you still owe the full loan at the end and need a separate plan to repay it. Interest-only mortgages are now rare for residential buyers and typically reserved for buy-to-let investors.
Why Your LTV Ratio Matters
LTV (Loan to Value) = mortgage amount ÷ property value × 100. The lower your LTV, the better the mortgage rate you can access. Key thresholds: 95% (minimum deposit most lenders accept), 90%, 85%, 80%, 75%, and 60%. Crossing below 75% and especially 60% LTV typically unlocks the best rates. Each 5% improvement in LTV can save 0.2–0.5% on your interest rate — worth calculating over a 25-year term.
The Power of Overpayments
Most UK mortgage products allow overpayments of up to 10% of the outstanding balance per year without penalty. Even £100/month extra on a £270,000 mortgage at 4.5% over 25 years saves approximately £18,000 in interest and shortens the term by 2–3 years. The earlier in the mortgage term you overpay, the greater the compounding benefit.
Fixed vs Variable Rates
Fixed rate: your payment stays the same regardless of Bank of England base rate changes — ideal for budgeting certainty. Tracker: moves with the base rate — lower when rates fall, higher when they rise. Discount: a set amount below the lender's standard variable rate (SVR). Most buyers choose a 2–5 year fixed rate then remortgage when the deal expires.
Frequently Asked Questions
How much deposit do I need for a mortgage?
Most UK lenders require a minimum 5% deposit (95% LTV), though rates improve substantially at 10%, 15%, 25%, and 40% deposit levels. A 5% deposit on a £300,000 property is £15,000; a 25% deposit on the same property is £75,000 and typically unlocks meaningfully better rates than a 5-10% deposit.
What's the difference between repayment and interest-only mortgages?
A repayment mortgage reduces your loan balance every month — by the end of the term, you own the property outright. An interest-only mortgage keeps payments lower but you still owe the full loan at the end and need a separate repayment plan. Interest-only mortgages are now rare for residential buyers and typically reserved for buy-to-let investors.
How does my loan-to-value (LTV) ratio affect my rate?
LTV = mortgage amount ÷ property value × 100. The lower your LTV, the better the rate you can access. Key thresholds are 95%, 90%, 85%, 80%, 75%, and 60% — crossing below 75% and especially 60% LTV typically unlocks the best rates available. Each 5% improvement in LTV can save roughly 0.2–0.5% on your interest rate.
Is it worth overpaying my mortgage?
Usually yes, if your mortgage allows it without penalty. Most UK mortgage products permit overpayments of up to 10% of the outstanding balance per year penalty-free. Even £100/month extra on a £270,000 mortgage at 4.5% over 25 years saves roughly £18,000 in interest and shortens the term by 2-3 years — use this calculator's overpayment field to model your own numbers.
Should I choose a fixed or variable rate mortgage?
A fixed rate keeps your payment identical for the deal period (typically 2, 5, or 10 years) regardless of what happens to interest rates, giving budgeting certainty. A variable/tracker rate moves with the Bank of England base rate (or the lender's own standard variable rate), which can fall as well as rise. Most UK buyers in a higher-rate environment favour fixed deals for the payment certainty; the trade-off is that you don't benefit automatically if rates fall during your term.
How much stamp duty will I pay on top of my mortgage?
Stamp Duty Land Tax (England/NI) depends on the property price and whether you're a first-time buyer, home mover, or buying an additional property — rates are banded and additional-property purchases carry a 3% surcharge on every band. Enter your property price and buyer type above (in the advanced fields) to see your estimated stamp duty alongside legal, survey, and removal costs in the Total Cost of Buying section below.
What other costs are there beyond the mortgage payment and deposit?
Budget for stamp duty (if applicable), solicitor/conveyancing fees (typically £1,200-2,200), a survey (£450-950 depending on property value and survey depth), removal costs, mortgage arrangement fees, and Land Registry fees. Together these one-off costs commonly add £3,000-6,000+ on top of your deposit — see the Total Cost of Buying breakdown below for an estimate based on your own figures.