Compare Two Mortgages

Choosing between two mortgage offers is rarely as simple as picking the lower headline rate. Fees, deal lengths and repayment type all change the real cost. Our compare two mortgages calculator lets you enter both offers side by side and see which genuinely comes out cheaper — both over the initial deal period and across the full mortgage term.

Why the Lowest Rate Is Not Always the Cheapest Deal

A mortgage with a slightly higher rate but a much lower fee can easily beat a “best buy” rate once you do the sums, especially on smaller loan amounts where a fixed fee makes up a bigger share of the total cost. For example, a 4.3% rate with a £1,999 fee might cost more over a two-year deal than a 4.5% rate with a £299 fee, once the extra fee is spread across the shorter period. This calculator does that maths automatically, so you are comparing genuine total cost rather than just the advertised rate.

Deal Period vs Full Term: Two Different Questions

It is worth comparing both figures this tool gives you. The “cost over the deal period” tells you what you will actually pay during the fixed or discounted period — the number that matters most if you plan to remortgage again once the deal ends. The “cost over the full term” assumes you stay on the same rate for the entire mortgage, which is unrealistic for most people but is useful for understanding the underlying interest rate cost if you were to never switch. Most borrowers should weight the deal-period comparison more heavily, since remortgaging every two to five years is now the norm in the UK rather than the exception.

Don’t Forget Product Fees

Product or arrangement fees typically range from £0 (fee-free products, usually at a slightly higher rate) up to £1,999 or more on some premium deals. These can often be added to the loan rather than paid upfront, but doing so means you pay interest on the fee too — a detail worth factoring in if you are torn between two very close offers.

A Worked Example

Mortgage A: £240,000, 4.6%, 2-year fix, £999 fee. Mortgage B: £240,000, 4.3%, 5-year fix, £1,499 fee. Over the deal period alone, Mortgage A costs less in total because the period is shorter, but the monthly payment on Mortgage B is lower and the rate is locked in for three extra years — valuable if you want payment certainty through a period of potential rate volatility. There is rarely a single “correct” answer; it depends how much you value payment stability against minimising short-term cost.

Using a Mortgage Broker to Widen Your Comparison

This calculator is designed for comparing two specific offers you already have in front of you, but it is worth remembering that not every mortgage deal is available directly to the public — a meaningful share of the market is only accessible through brokers, including some competitive rates from smaller building societies and specialist lenders. A whole-of-market broker can search across the full range of available products, then you can bring the two or three best candidates back to this calculator to compare in detail. Brokers are typically paid either by a fee, a commission from the lender, or a combination of both, so it is worth asking upfront how your particular broker is remunerated.

It is also worth checking whether either mortgage you are comparing includes any incentives — cashback, free legal fees, or a free valuation — since these can shift the overall value of a deal even when the headline rate and fee look similar to a competing offer.

Frequently Asked Questions