UK Mortgage Calculator
Calculate your UK mortgage monthly payment including Stamp Duty Land Tax (SDLT). Choose between repayment and interest-only mortgages and see how your payment changes when your fixed rate reverts to the lender's Standard Variable Rate (SVR). Supports amortization periods from 20 to 35 years.
You might also need
How It Works
A repayment (capital and interest) mortgage reduces both the interest and the outstanding loan balance with each payment. After the full term, the loan is completely paid off. This is the most common UK mortgage type.
M = P × r(1+r)^n / [(1+r)^n - 1]£280K at 4.5% over 25yr = £1,556/moInterest-only payments cover just the monthly interest. The loan balance stays constant throughout the term. Monthly payments are significantly lower, but the full loan must be repaid at the end through a separate repayment vehicle.
Monthly = Loan × (Rate / 12)£280K at 4.5% interest-only = £1,050/mo (£506 less)SDLT applies in England on properties over £250,000. It is tiered — you pay 5% on the band from £250,001 to £925,000, 10% from £925,001 to £1,500,000, and 12% above £1,500,000. First-time buyer relief applies on purchases below £625,000.
SDLT = Σ(Band Amount × Band Rate)£500K purchase: (£500K-£250K) × 5% = £12,500Loan-to-value divides the mortgage amount by the property value. Lower LTV means more equity and better mortgage rates. The 60% and 75% LTV thresholds are key — crossing below them typically unlocks significantly better rates.
LTV = (Loan / Property Value) × 100£280K mortgage on £350K property = 80% LTVWhen a 2 or 5 year fixed rate expires, the mortgage reverts to the SVR. The calculator shows the new payment at the SVR to reveal the payment shock if you do not remortgage. Most borrowers remortgage 3 to 6 months before the fix ends.
Revert payment = remaining balance amortized at SVR£280K at 4.5% fixed → 7.5% SVR: £1,556 → £2,058/moAdd SDLT to total mortgage interest paid over the term for the complete cost of buying the property. This helps compare buying versus renting over the same period.
Total = SDLT + (Monthly × Months)£12,500 SDLT + £186,800 interest = £199,300 total costQuick Reference
Common examples — verify instantly above.
£350K, 4.5%, 25yr repay
Monthly payment
£1,944/mo
£350K, 4.5% interest only
Monthly payment
£1,313/mo
LTV check
£280K on £350K property
80% LTV
SDLT on £500K
England (no first-time buyer)
£12,500
SDLT on £350K
England (no first-time buyer)
£5,000
SVR revert
£280K, 4.5% → 7.5%
£1,556 → £2,058/mo
25yr vs 35yr
£350K at 4.5%
£1,944 vs £1,572/mo (£70K more interest)
80% vs 60% LTV
Rate difference benefit
~0.5-1% lower rate at 60% LTV
Tips & Shortcuts
Remortgage 3 to 6 months before your fixed rate ends. Starting early gives time to find the best deal and complete the process before reverting to the expensive SVR.
Use a mortgage broker to access the whole market. Many competitive deals are only available through brokers, not directly from lenders.
Target the 60% or 75% LTV threshold if you are close. Even a slightly larger deposit to cross these thresholds often reduces the rate enough to justify the extra upfront cost.
Consider a 5-year fix if you value payment certainty. The rate is slightly higher than a 2-year fix but provides longer security against rate rises.
First-time buyer SDLT relief is available on properties up to £625,000 in England. The saving can be up to £11,250 — verify eligibility before completion.
Interest-only mortgages require a credible repayment plan. Lenders require evidence of how the loan will be repaid at the end of the term — typically an investment portfolio, pension lump sum, or property sale proceeds.
Common Mistakes to Avoid
Not accounting for stamp duty in the total purchase budget
SDLT on a £500,000 property is £12,500, payable within 14 days of completion. Factor this into your deposit calculation alongside legal fees, survey costs, and moving expenses.
Reverting to the SVR without remortgaging
The SVR is typically 2% to 3% higher than fixed rates. On a £280,000 mortgage, this adds £350 to £500 per month. Set a diary reminder 6 months before your fix ends.
Choosing interest-only without a credible repayment vehicle
Interest-only means the full loan remains at term end. Without a solid repayment plan, you face forced sale of the property. Lenders now require proof of the repayment strategy.
Not checking LTV when remortgaging
House price changes can move your LTV significantly. If your property has risen in value, you may qualify for a much better LTV band. Get a current valuation before remortgaging.
Ignoring arrangement fees when comparing deals
Some low-rate mortgages have arrangement fees of £1,000 to £2,000. On a small mortgage or short fixed period, the fee may outweigh the rate saving. Always calculate the total cost including fees.
Not using a solicitor who specializes in property conveyancing
Cheap online conveyancing services often cause delays that cost more than the savings. A specialist solicitor reduces the risk of chain collapses and unexpected delays.
Frequently Asked Questions
SDLT applies to properties over £250,000. You pay 5% on the portion between £250,001 and £925,000, 10% on the portion between £925,001 and £1,500,000, and 12% on the portion above £1,500,000. First-time buyers get relief on properties up to £625,000. Scotland uses Land and Buildings Transaction Tax (LBTT) and Wales uses Land Transaction Tax (LTT) with different rates.
UK mortgages typically have shorter initial fixed terms of 2 to 10 years, after which they revert to the lender's SVR. US mortgages are more commonly fixed for the full 30-year term. UK mortgages also have maximum amortization periods typically capped at 35 to 40 years, and mortgage insurance works differently.
Loan-to-value ratio is the loan amount as a percentage of the property value. UK lenders offer better rates at lower LTVs: 60% LTV gets the best rates, 75% gets good rates, 90% still qualifies but with higher rates and fewer lender options. Above 90%, options become very limited.
An interest-only mortgage requires only the monthly interest payment, with no principal reduction. The full loan amount remains outstanding and must be repaid at the end of the term, typically through a savings plan, investment, or property sale. Monthly payments are lower but the total cost is higher since no equity is built through payments.
When the fixed-rate period ends, the mortgage reverts to the lender's Standard Variable Rate (SVR), which is typically 1.5% to 3% higher than the fixed rate. Most borrowers remortgage before the reversion date to avoid the SVR. The revert rate field shows the payment jump if you do not remortgage.
Some UK lenders offer mortgages to non-residents and expats, but options are limited and rates are higher. A larger deposit (25% to 40%) is typically required. Specialist mortgage brokers who focus on expat mortgages are the best starting point.
Related Calculators
House Affordability Calculator
Find out how much home you can afford based on income.
Canadian Mortgage Calculator
Mortgage payment using Canadian compounding rules.
Payment Calculator
Find monthly payment for any loan amount and term.
Mortgage Payoff Calculator
See how extra payments shorten your loan and save interest.
FHA Loan Calculator
FHA monthly payment including MIP and lower down payment.
VA Mortgage Calculator
VA loan payment with no PMI and zero down payment option.