Key Takeaway

Guarantor mortgages require a family member or friend to guarantee your repayments if you cannot pay, while family deposit products involve a relative depositing savings (typically 10% of the property value) into a linked account for a fixed term. Guarantor mortgages carry greater personal risk for the guarantor, who may be liable for the full mortgage debt. Family deposit schemes protect the family member’s cash, which is returned with interest after the initial period, but tie up their savings for several years. Both routes help first-time buyers overcome deposit or affordability barriers, but the right choice depends on your family’s financial position and risk tolerance.

Understanding Guarantor Mortgages

A guarantor mortgage allows you to borrow when you have a small deposit or limited income by having a guarantor (usually a parent or close relative) promise to cover your mortgage repayments if you default. According to MoneyHelper, the guarantor typically needs to be a homeowner with a strong credit history and sufficient income to afford both their own commitments and your mortgage repayments if required.

The guarantor does not make monthly payments under normal circumstances. They step in only if you miss payments. However, their liability can be substantial: if you fall into arrears, the lender can pursue the guarantor for the full outstanding debt, and the guarantor’s own home may be at risk if they secure the guarantee against their property.

Guarantor mortgages suit first-time buyers who can afford monthly repayments but lack a large deposit or have a short credit history. The guarantor’s financial strength compensates for your lower deposit or income, allowing lenders to offer loan-to-value ratios of 95% or even 100% in some cases.

What Are Family Deposit Products?

Family deposit mortgages (also called family springboard or family offset mortgages) involve a relative depositing a sum of money (typically 10% of the property purchase price) into a savings account linked to your mortgage. This deposit acts as security for the lender, allowing you to borrow up to 100% of the property value without needing your own deposit.

The family member’s savings remain in the account for a fixed term, usually three to five years. During this period, they cannot access the money, but it earns interest (often at a competitive rate). At the end of the term, if you have kept up with all repayments, the family member receives their deposit back in full, plus any accrued interest.

According to the Financial Conduct Authority, these products reduce risk for the family member compared to guarantor mortgages because their maximum loss is limited to the deposited amount. If you default, the lender uses the deposited funds to cover arrears, but the family member is not liable for any additional debt beyond their initial deposit.

Comparing the Two Approaches

The fundamental difference lies in risk and control. Guarantor mortgages expose the guarantor to unlimited liability for your debt. If you stop paying and the property is repossessed and sold at a loss, the guarantor may owe the lender the shortfall, which can run into tens of thousands of pounds.

Family deposit products cap the family member’s risk at the amount deposited. They cannot lose more than they put in, and they regain their money if you maintain payments. However, this approach requires the family member to have substantial savings available and willing to lock them away for several years.

Read also: A First-Time Buyer’s Guide to Getting a Mortgage in the UK

Guarantor mortgages require no upfront cash from the guarantor, making them accessible to family members who are asset-rich but cash-poor (for example, a parent who owns their home outright but has limited savings). Family deposit schemes, by contrast, suit relatives with accessible savings who prefer defined risk over open-ended liability.

From the borrower’s perspective, both routes can unlock 95% to 100% loan-to-value mortgages and make homeownership possible sooner. The monthly repayments fall entirely on you in both cases. As foundational texts such as Principles of Finance explain, leveraging family support can bridge the affordability gap for first-time buyers, but all parties must understand the financial obligations and risks before proceeding.

How a Mortgage Affordability Calculator Helps

Before committing to either option, you need to understand how much you can realistically afford to borrow and repay each month. Lenders assess your income, existing debts, and monthly outgoings to determine your maximum loan. A mortgage affordability calculator lets you model different scenarios: your income level, deposit amount, interest rate, and loan term.

By entering your details, you can see the estimated monthly repayment and the maximum loan you might qualify for. This helps you and your family member decide whether a guarantor mortgage or family deposit product is necessary, and which one suits your circumstances. For example, if the calculator shows you can afford repayments on a 95% loan-to-value mortgage but lack the 5% deposit, a family deposit product might be ideal. If you can afford repayments but your income alone does not meet the lender’s criteria, a guarantor mortgage could bridge that gap.

The calculator also highlights the importance of budgeting for additional costs such as arrangement fees, valuation fees, conveyancing, and stamp duty land tax, which vary depending on the property price and your status as a first-time buyer. Understanding your true affordability prevents overcommitting and reduces the risk of default, protecting both you and your family member.

Next Steps and Important Warnings

Both guarantor mortgages and family deposit products are specialist schemes offered by a limited number of lenders. Availability, eligibility criteria, interest rates, and terms vary significantly. According to MoneyHelper, you should compare products carefully and consider speaking to an FCA-authorised mortgage adviser who can assess your circumstances and recommend suitable lenders.

Your home may be repossessed if you do not keep up repayments on your mortgage. This warning applies to guarantor mortgages as well: if you default and the guarantor has secured the guarantee against their own property, their home is also at risk.

The information in this article is general educational guidance and is current as of August 2026. It is not regulated mortgage advice, personalised financial advice, or legal advice. Refisage is not authorised by the Financial Conduct Authority. Mortgage products, rates, eligibility criteria, and scheme availability change frequently. Always verify current terms and your personal eligibility with an FCA-authorised mortgage adviser before deciding. Government schemes, stamp duty rules, and affordability requirements differ across England, Scotland, Wales, and Northern Ireland, and individual circumstances vary by lender, product, and your financial profile.