Let to Buy Mortgages in the UK: How They Work in 2026

Let to buy is a useful route for people who want to keep their current home as a rental while moving into a new one, rather than selling. It involves two mortgages and a stamp duty surcharge, so it pays to understand the costs first.

What let to buy means

In a let to buy arrangement you:

1. Remortgage your current home onto a buy to let mortgage so you can legally rent it out
2. Take a new residential mortgage on the home you move into

You then hold two properties and two mortgages. It differs from a straight buy to let, where you buy a property purely to rent rather than converting your existing home.

Why people choose it

• They expect their current home to rise in value and want to keep it
• They are moving for work or family but may return
• They cannot sell quickly and want to move without a chain
• They want rental income to help cover the new costs

The deposit and equity side

The buy to let part usually needs around 25% equity in the property. Many people release this equity by remortgaging the old home and using the freed-up cash as the deposit on the new residential purchase.

Lenders assessing the buy to let mortgage will look at expected rent rather than just your salary, typically wanting the rent to comfortably exceed the mortgage interest under a stress test.

The stamp duty surcharge matters

Because you keep the first property, the new home counts as an additional property for stamp duty in England and Northern Ireland. That means the 5% additional property surcharge applies on top of standard SDLT rates.

Worked example

Suppose you buy a new main home for GBP 350,000 under let to buy. Standard SDLT in England is 0% to GBP 125,000, 2% to GBP 250,000 and 5% above that. The 5% surcharge applies to the whole price.

• Standard SDLT: GBP 0 on the first GBP 125,000, GBP 2,500 on the next GBP 125,000 (2%), GBP 5,000 on the final GBP 100,000 (5%) = GBP 7,500
• Surcharge: 5% x GBP 350,000 = GBP 17,500
• Total SDLT: GBP 7,500 + GBP 17,500 = GBP 25,000

That GBP 17,500 surcharge is a major cost and is not refundable when you keep the old home, so factor it in early.

Things to weigh up before committing

• You will be a landlord, with the responsibilities and tax that brings
• Rental income is taxable and mortgage interest relief for individuals is limited
• Two mortgages mean two sets of rate risk at renewal
• The SDLT surcharge adds a large upfront cost on the new purchase

Is let to buy right for you

Let to buy can work well if you genuinely want to keep the first home as a long-term investment and the numbers stack up after the surcharge and landlord costs. If you simply need to move, selling may be cheaper and simpler.

To estimate the SDLT on your new home and model the buy to let figures, use the CalcHub stamp duty and mortgage calculators, and check the official rules on additional property SDLT and landlord tax at gov.uk.