Mortgage Deal Comparison
Compare two UK mortgage deals by true total cost, not just headline rate. Enter the interest rate, arrangement fee and initial term for each deal — the calculator combines monthly payments and upfront fees into a single cost-per-year figure so you can see which is genuinely cheaper.
Which deal costs the least?
Initial period cost breakdown
Bar height = total initial period cost. Grey = principal repaid. Coloured = interest paid. Red = arrangement fee. Label above each bar shows cost per year.
What to bear in mind
Initial period cost doesn't tell the whole story — you'll need to remortgage when the deal ends, and the rate then is unknown. The winner here is the cheapest deal during the initial fixed or tracker term only. A lower rate with a higher fee can still be cheaper overall if the product term is long enough; this calculator shows you exactly when that crossover happens via cost-per-year. At the end of the initial term, most lenders move you onto their Standard Variable Rate (SVR), which is typically 1–2% higher than the best available deals — set a reminder to remortgage before the deal expires.
Mortgage brokers worth considering
Disclosure: links below are affiliate links — we may earn a commission at no cost to you. We only list services we'd genuinely consider.
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How to properly compare mortgage deals
Most people compare mortgages on monthly payment or headline rate — but both can mislead. A 2-year fix at 4.2% with a £999 fee might cost more per year than a 5-year fix at 4.5% with no fee. This calculator does the maths: it divides the total cost of the initial period (payments plus fee) by the number of years to give a single comparable figure.
Why arrangement fees matter more than you think
A £999 arrangement fee on a 2-year deal adds £500 per year to your effective cost. On a 5-year deal, the same £999 fee adds only £200 per year. This is why the headline rate alone is not enough — a no-fee deal at a slightly higher rate can easily beat a low-rate deal with a large fee, especially on shorter product terms. Always check the fee-free alternative from the same lender before deciding.
True cost calculation method
This calculator computes the monthly payment using the standard annuity formula (based on your full remaining term), then multiplies by the product term months to get total payments during the initial period. Adding the arrangement fee gives total initial cost. Dividing by product term years gives cost per year — the fairest comparison across deals of different lengths.
The SVR danger
Standard Variable Rates (SVRs) are set by each lender and can change at any time. The average UK SVR has historically sat 3–5 percentage points above the Bank of England base rate. Falling onto an SVR after your initial deal ends can add hundreds of pounds per month to your payment. Remortgaging 3–6 months before your deal expires avoids this.
Fixed vs tracker mortgages
A fixed-rate mortgage gives payment certainty for the product term — your rate won't change even if the Bank of England raises rates. A tracker mortgage follows the base rate plus a set margin, so payments rise and fall. Trackers sometimes offer lower initial rates but carry more risk. In a falling rate environment, trackers win; in a rising rate environment, fixed rates protect you.
Remaining balance after the initial period
This calculator shows the balance remaining at the end of the initial deal period. This is the amount you'll need to remortgage — important for planning ahead. A lower rate reduces the balance faster (more of each payment goes to principal), so a cheaper initial deal also leaves you with a slightly lower outstanding balance to remortgage.
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