Mortgage Calculator

Each monthly payment covers two things: interest charged on the outstanding balance, and a slice of the capital itself. In the early years most of your payment is interest; by the final years almost all of it is capital. This pattern — called an annuity schedule — means the balance falls slowly at first, then much faster toward the end. Worked example. Borrow £250,000 over 25 years at 4.5%: monthly repayment = £1,389. Over the full term you pay back £416,621 — meaning £166,621 in total interest, 67% on top of the amount borrowed. Reducing the term to 20 years cuts the total interest to £123,683 (saving £42,938) but raises the monthly payment to £1,582.

With an interest-only mortgage you pay only the interest each month; the capital remains unchanged. Monthly payments are lower (£937/month on the same £250,000 at 4.5%) but at the end of the term you still owe the full £250,000 and must repay it — typically by selling the property or using an investment vehicle. Lenders require a credible repayment plan and many restrict interest-only to higher loan-to-value ratios. Switch to the Interest-only tab in the calculator to compare.

SDLT is the main upfront cost when buying in England or Northern Ireland (Scotland has LBTT; Wales has LTT). Rates from October 2025:

• £0–£125,000: 0%
• £125,001–£250,000: 2%
• £250,001–£925,000: 5%
• £925,001–£1.5m: 10%
• Over £1.5m: 12%

First-time buyers pay 0% up to £300,000 and 5% on the portion from £300,001 to £500,000 (no relief above £500,000). The calculator applies the sliding scale automatically based on the property value you enter. Source: HMRC Stamp Duty Land Tax rates

Most UK lenders use an income multiple of 4–4.5× your gross annual household income as their upper limit, subject to an affordability stress-test at the lender's standard variable rate plus 3 percentage points (the FCA's minimum stress rate). Use the Affordability tab to work backwards from a monthly budget to a maximum loan size. As a rule of thumb, lenders also require a minimum deposit of 5% (95% LTV), though rates improve significantly at 75–80% LTV. Below 85% LTV, HSBC and Barclays typically offer competitive fixed deals; above 90% LTV you'll generally pay a premium of 0.5–1.0 percentage points.

Most lenders allow overpayments of up to 10% of the outstanding balance per year without an early repayment charge (ERC). Even a modest extra £100/month on a £250,000 25-year mortgage at 4.5% saves around £23,000 in interest and cuts the term by over two years. Toggle Add overpayment in the calculator to see your own numbers immediately.

Mortgage Guarantee Scheme: The government guarantees part of the loan for lenders offering 91–95% LTV mortgages, widening the availability of high-LTV products. Available on properties up to £600,000. Lifetime ISA (LISA): Save up to £4,000/year before age 40 and receive a 25% government top-up (£1,000/year maximum). Use it toward a first home purchase up to £450,000. Withdrawals for other purposes incur a 25% penalty. Shared Ownership: Buy a share (10–75%) of a property and pay rent on the rest. You can "staircase" toward full ownership over time. Eligibility conditions apply.