Let-to-Buy Mortgage FAQ
General information only. This is not financial advice.
Last reviewed: 2026-06-06
What is a let-to-buy mortgage?
Let-to-buy is a property strategy where you retain your existing home by switching its mortgage from a residential to a buy-to-let product, and simultaneously take out a new residential mortgage to purchase a different property to live in. The equity released from the original property — either from the buy-to-let remortgage or from existing equity — can then form part of the deposit on the new home. The two transactions are coordinated to happen at the same time, which makes let-to-buy more complex than a straightforward purchase or remortgage.
How does the let-to-buy process work step by step?
The process typically works as follows: (1) You approach a buy-to-let lender about switching your existing residential mortgage to a BTL product, potentially releasing equity to use as a deposit. (2) You approach a residential mortgage lender about the new property you wish to buy, using the equity released plus any additional savings as the deposit. (3) If both lenders are satisfied, both mortgage offers are issued. (4) Completion is coordinated so that the residential mortgage on your current home switches to the BTL product on the same day you complete on the new residential purchase. The key challenge is timing — both transactions must align, and any delays on one side can affect the other.
Will I have to pay the higher rate of stamp duty on a let-to-buy purchase?
Yes, in almost all let-to-buy cases. Because you will own two properties at the time you complete on the new residential purchase, HMRC charges the additional dwellings supplement — currently 3% extra on top of standard stamp duty rates. This can add a significant cost. For example, on a £300,000 purchase, the additional 3% adds £9,000 to your stamp duty bill. The only exception would be if you sold your original property before completion, which would defeat the purpose of let-to-buy. You should factor the additional stamp duty cost into your financial planning before proceeding.
Can I use the rental income from my current home to support the new residential mortgage?
Some residential mortgage lenders will consider rental income from the let-to-buy property when assessing affordability for the new home purchase, but this is not universal. The rental income is typically included only if you have an existing track record as a landlord, or if the lender is satisfied that the rental yield is credible. For new let-to-buy arrangements where you have not previously been a landlord, many lenders assess the new residential mortgage based on your employment income alone — which must be sufficient to cover both the new residential mortgage payment and, in some cases, a deemed rental figure for your existing property.
What equity do I need in my current home for a let-to-buy to work?
You need enough equity in your current property to meet two requirements: first, the buy-to-let lender's minimum LTV for the BTL mortgage (typically 75%, meaning at least 25% equity must remain in the property after any equity release); and second, sufficient equity to contribute meaningfully to the deposit on the new home. If your current home has 50% equity, for example, you could remortgage it to 75% LTV, releasing 25% as equity — which could then be used as part of the deposit on the new purchase. The viability of let-to-buy depends heavily on how much equity you have built up in your current property.
Do all lenders offer let-to-buy mortgages?
Not all lenders will support the simultaneous let-to-buy structure, and some lenders are more experienced with it than others. On the buy-to-let side, you need a lender who will accept a simultaneous consent-to-let switch (converting a residential mortgage to BTL) rather than requiring you to sell first. On the residential side, you need a lender who will consider your application even though you are not selling the existing property and will be owning two homes. A specialist mortgage broker who has arranged let-to-buy transactions before can identify which lenders in the market are suited to both sides of the transaction and manage the coordination between the two lenders.
Risk warning
Your home may be repossessed if you do not keep up repayments on your mortgage. Think carefully before securing other debts against your home. This article is general information only and does not constitute financial advice.
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