NatWest and Rightmove agree mortgage partnership deal | Here's why using one mortgage calculator isn’t enough for a full market view

by Aaron Strutt

Feb 06 2026

When you're scrolling through Rightmove at midnight, dreaming about that Victorian terrace or new-build flat, the temptation to click the big "find out what you can borrow" or get an "agreement in principle" button is almost irresistible. From April 2026, NatWest will be the exclusive mortgage lender on one of Britain's most-visited property portals.

Rightmove’s mission is to "digitise more of the UK property market, helping speed up the home-moving process through innovative technology solutions." The mortgage in principle offering from NatWest will join a suite of affordability tools on Rightmove, including stamp duty, mortgage, and renovation calculators, as well as instant and in-person property valuation tools. NatWest is replacing Nationwide as the current mortgage partner and aims to help users understand what they could borrow.

Why one mortgage calculator or agreement in principle system isn’t enough for a full market view

Having a single mortgage affordability calculator or a single Mortgage in Principle partner on a property website can be a very useful starting point for potential buyers. It helps people estimate how much they might be able to borrow based on income, expenses and other factors. However, if that calculator is tied to a single lender or provider, there are important limitations that mean it won’t show the full range of mortgage deals available in the market. This is importanant especially as Moneyfacts data shows the total number of mortgages rose above 7,500 by the start of February.

Recent research from the Building Societies Association (BSA) shows that many aspiring buyers could be closer to owning their own home than they think, but too many are ruling themselves out before exploring what is possible. The findings show that almost half (47%) of people who want to buy their own home have never spoken to a lender or mortgage broker to check what options are available to them. Even among those who have, around half (46%) have not done so in the last year.

Mortgage in principle tie-ups often reflect one lender’s products

A calculator that’s linked to NatWest will primarily show affordability and potential borrowing based on NatWest’s mortgage criteria and products. Even if it includes some general figures or estimates, it’s not designed to compare all lenders’ deals.

Aaron Strutt, product director at Trinity Financial, says: "NatWest has grown to become the 3rd largest mortgage provider in the UK, and it often has a selection of the lowest mortgage rates and now some really generous maximum loan sizes. The issue is that there is so much competition in the market at the moment that it is clearly not going to be able to highlight the best options for all borrowers. This means its system on Rightmove will not show the criteria from other high-street banks, Barclays, HSBC, Santander UK, that aren’t automatically included.

"Building societies and online lenders, which often have competitive rates, won’t be shown unless separately integrated. Specialist products like first-time buyer schemes, lowest-deposit mortgages, or green mortgages are unlikely to feed into the same calculator. Here are some of the best first-time buyer schemes on the market at the moment."

Rate availability and product terms vary widely

Even if a calculator estimates how much you could borrow, the interest rates and fees attached to actual deals differ across lenders — sometimes significantly.

• Market rates change frequently based on supply, demand and macro-economic conditions. Today’s cheapest rate may not be offered by NatWest but by a competitor.

• Some lenders offer incentives (e.g., cashback, fee waivers, green or offset products) that a single provider’s tool won’t factor in.

A single calculator cannot reflect this range of variables — especially when it’s tied into one provider’s products.

No substitute for a full mortgage search

Trinity Financial's brokers search thousands of products across the whole market. These tools take into account: Different interest rate types, fixed, trackers, offsets and flexible rates without early repayment charges. Loan-to-value brackets with low or no-deposit mortgages. Fees and incentive packages, including cashback, higher-fee and lower-rate products, plus affordability criteria from each lender.

A single calculator does not have the capability to do this breadth of comparison. For example, a mortgage broker might find a lower rate at 90% loan-to-value with one lender but a better fixed-rate deal at 75% loan-to-value with another — insights a single-provider calculator often won’t surface.

Consumer awareness and behaviour

A single calculator situated on Rightmove has a wide reach — but homeowners may assume it shows the “best or most generous” deals, when in reality it reflects one provider’s offering or range. Standing alone, it can create a perception that NatWest’s deals are the only ones relevant to their situation and even lead to missed opportunities with other lenders better positioned for a borrower’s profile. This is especially true for first-time buyers or financially inexperienced borrowers who don’t yet know to check multiple sources.

Lending solutions with Trinity Financial

Are you looking to buy a property and require expert advice? We’re here to help you find a solution – no matter how complex your circumstances. Our expert brokers have extensive experience providing creative solutions to secure mortgages for our clients.

Call Trinity Financial on 020 7016 0790 to secure a more generous mortgage, book a consultation or use our appointment calendar

The information contained within was correct at the time of publication but is subject to change.

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