The deposit is the part of a purchase not funded by the mortgage. The amount needed depends on the accepted loan and complete transaction, rather than one percentage applying to every buy-to-let property.
Start with the purchase price, likely valuation, rental evidence and other costs. This makes it easier to see which figures are confirmed and which could change.
Worked deposit example: purchase price and valuation differ
Hypothetical arithmetic only. Suppose a property price is £200,000 and a proposed mortgage is £150,000. The gap to the price is £50,000 before any other costs. If the lender’s valuation is £190,000, that same loan is approximately 78.95% of the valuation, rather than 75%.
| Illustrative basis | Calculation | Result |
|---|---|---|
| Original price comparison | £150,000 ÷ £200,000 × 100 | 75% loan-to-price; this is not necessarily the lender’s valuation basis. |
| Lower valuation comparison | £150,000 ÷ £190,000 × 100 | Approximately 78.95% loan-to-valuation. |
| If a hypothetical 75% limit applied to that valuation | £190,000 × 75% | £142,500 maximum under that assumed limit alone. |
| Gap to the unchanged price | £200,000 − £142,500 | £57,500 before separate purchase costs. |
The 75% limit is an invented assumption, not a statement that every buy-to-let lender offers that loan-to-value. Actual borrowing can also be restricted by rental assessment, credit, property and other requirements. A larger deposit does not resolve those automatically.
Keep cash, equity and costs in separate columns
Record the purchase-price contribution, fees and taxes, and any money retained for ongoing ownership costs separately. A single savings balance cannot be allocated in full to all of them. Equity in another property is not the same as available cash; any proposed additional borrowing has separate costs and risks.
For mixed savings and family contributions, use the source-of-funds record-chain example. The proposed ownership structure and tax consequences need appropriate individual advice.
Buy-to-let deposit requirements: Understand loan-to-value
Loan-to-value compares borrowing with the property value used by the lender. The agreed purchase price and accepted valuation are not necessarily the same.
If the valuation is lower, the personal funds needed can rise even without a price change. A deposit percentage calculated only from the asking price can therefore be misleading.
A product maximum is a limit subject to its terms. It does not establish that the lender will advance the maximum on a particular application.
Expect more than one borrowing limit
Rental assessment can restrict the loan below the product’s maximum loan-to-value. The lender may use its own rent figure and borrowing-cost assumptions.
Income, credit history, property type and landlord experience can also affect acceptance. No deposit amount automatically removes those checks.
Keep the different limits distinguishable. A calculation showing sufficient equity does not prove sufficient rent or acceptable credit.
Identify the source of funds
Savings, a gift and proceeds from another sale may need different evidence. The lender and legal team decide what documents they require.
A recent account transfer is not always the complete explanation. Keep records showing how the money was obtained and moved.
If funds depend on another transaction, state its stage accurately. Expected proceeds are different from cleared money available for completion.
Explain gifts and borrowing clearly
A genuine gift and a loan create different obligations. Any conditions or expected repayment need to be disclosed accurately.
Borrowed deposit funds may not be permitted and can affect commitments. Do not assume calling a transfer “family help” answers the lender’s questions.
This guide does not recommend new borrowing, using home equity or a particular source of deposit. Those choices can have consequences beyond meeting a purchase calculation.
Include costs outside the deposit
Legal fees, valuation, product charges and applicable taxes can need additional funds. Work required before letting can add another funding requirement.
Some charges may be payable even if the purchase does not complete. Read the relevant terms and ask for a clear breakdown.
If a fee is proposed to be added to borrowing, the lender must accept it. Added fees can increase the balance and interest paid.
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This is an initial enquiry for administrative support and an adviser introduction where appropriate. It is not a mortgage application or an eligibility assessment. Any mortgage advice comes separately from an adviser acting through an FCA-authorised and regulated network. The receiving firm explains its service, fees and information requirements.
Mortgage Bridge has commercial relationships with receiving firms and receives a percentage of the adviser’s commission when an introduced case completes. Acceptance is not guaranteed.
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Send details of your enquiry for administrative support and an adviser introduction where appropriate. Mortgage Bridge does not provide mortgage or debt advice, assess eligibility, affordability or suitability, or recommend products. Mortgage advice comes from an adviser acting through an FCA-authorised and regulated network.
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Mortgage Bridge has commercial relationships with receiving firms and receives a percentage of the adviser’s commission when an introduced case completes.
Your home may be repossessed if you do not keep up repayments on your mortgage.
Avoid counting the same money twice
Funds allocated to the deposit cannot also cover repairs, debts or transaction costs unless enough is genuinely available. A written allocation can reveal a shortfall.
If the mortgage advance changes, revisit the whole calculation. The deposit gap and other costs may need funding at different times.
Keep estimates labelled until confirmed. An intended gift, expected valuation and quoted cost are not all equally certain.
Consider ownership costs after completion
Mortgage payments can start before rent arrives. Repairs, insurance, service charges and management costs may also arise during a vacancy.
Gross rent is different from profit or cash remaining. A completed purchase does not guarantee immediate occupancy or uninterrupted payments.
A larger deposit does not establish that the investment suits an individual. It reduces borrowing relative to value but does not remove every financial risk.
Review the mortgage commitment
Compare the rate, fees, term, repayment basis and early repayment conditions. A lower monthly amount may involve a longer term and more interest overall.
With interest-only borrowing, regular payments do not repay the capital. The balance remains due, while future refinancing and sale value are uncertain.
State the intended use accurately. Personal or family occupation can affect mortgage type and regulation, regardless of the deposit size.
Prepare the complete application
Gather deposit records, income and commitment evidence, credit information, property details and rental estimates. Add a breakdown of purchase costs and any required work.
Identify dependencies on other transactions and documents. If the lender accepts a lower rent or value, establish what that does to the personal funds required.
An adviser acting through an FCA-authorised and regulated network can assess mortgage options within their service. Mortgage Bridge provides introductions and administrative support rather than prescribing a deposit target or guaranteeing acceptance.
Buy-to-let mortgage deposits: rental income and buy-to-let underwriting
A buy-to-let assessment can consider achievable rent, mortgage costs, property expenses, the borrower and other commitments. A rent estimate is not guaranteed income. A lender’s rental coverage calculation and stress assumptions can differ from the landlord’s actual cash flow, and neither a single percentage nor a headline yield establishes acceptance.
Voids, arrears, repairs, management charges and tax can affect the amount left after costs. Interest-only payments do not repay the capital balance, which remains due under the loan terms. Personal income, other properties and wider portfolio commitments may also be relevant. This guide does not recommend property investment or present an anticipated rent increase, sale or refinance as a guaranteed repayment plan.
Frequently asked questions
Is there one deposit percentage for every buy-to-let mortgage?
No. Product, property, rental assessment and borrower criteria affect the requirement.
Can the valuation change how much cash I need?
Yes. A lower accepted value can reduce borrowing and increase the funding gap.
Does a larger deposit guarantee a mortgage?
No. Credit, rent, property and other lender requirements still apply.
Important information and Mortgage Bridge’s role
Mortgage Bridge provides general information and administrative support as a mortgage introducer. It does not provide mortgage or debt advice, assess eligibility, affordability or suitability, or recommend products. Mortgage advice comes from an adviser acting through an FCA-authorised and regulated network.
Mortgage Bridge has commercial relationships with receiving firms and receives a percentage of the adviser’s commission when an introduced case completes.
Your home may be repossessed if you do not keep up repayments on your mortgage.
Securing previously unsecured debts against a home increases the risk to the home. Lower monthly payments do not necessarily mean lower total costs. Longer repayment terms and fees can increase the total amount repaid.
Free, independent debt advice is available through MoneyHelper’s debt advice locator. Business Debtline explains its business-debt services and geographical coverage.
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Buy-to-let information
Most business buy-to-let mortgages are not regulated by the FCA in the same way as residential mortgages. Consumer buy-to-let has a separate framework, and some arrangements involving personal or family occupation can fall within residential mortgage regulation. The actual purpose, security and occupation determine the position; using an authorised firm does not make every loan regulated.
Rental income, property growth and future refinancing are not guaranteed. A rental property securing borrowing can also be repossessed if repayments are not maintained. Mortgage Bridge does not recommend an investment, ownership structure or tax strategy. Legal and tax advice are separate from mortgage advice.
Sources and review
Review date: 26 October 2026. Information and lender criteria may change. General information only; not a personal recommendation.
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