Mortgage deposit and LTV: how much you need and what it changes

What loan-to-value means

Loan-to-value (LTV) is the mortgage expressed as a percentage of the property's price or valuation, whichever is lower. A £285,000 loan on a £300,000 property is 95% LTV; the remaining 5%, or £15,000, is the deposit. Lenders cap LTV because it sets how much equity cushion exists if the property has to be repossessed and sold – a smaller deposit leaves less margin if prices fall.

UK lenders commonly go up to 95% LTV on mainstream residential products, which makes a 5% deposit the practical floor for most buyers. Some schemes and lenders go higher in specific circumstances, but 95% is the standard ceiling this calculation assumes.

Two caps, one binding limit

A UK mortgage offer is never set by LTV alone. Lenders also cap the loan at a multiple of gross annual income – typically 4.5 times combined income (see the affordability guide for how that cap works). The lender calculates both the loan-to-income (LTI) maximum and the LTV maximum, then offers whichever is smaller. Only one of the two is ever actually the reason you can't borrow more.

Worked example: when LTV is the binding cap

Take a £300,000 property and a combined gross income of £70,000 (for example £40,000 and £30,000). At the standard 4.5× multiple, the income cap alone would allow up to £315,000 – more than the property costs. In that situation, the deposit and LTV cap become the actual constraint, because the loan can never exceed the property price minus the deposit.

In every row above, the maximum loan equals the property price minus the deposit – the LTV cap is binding throughout, because £315,000 of income headroom is never the smaller number. Increasing the deposit here doesn't increase how much you're allowed to borrow beyond what you need; it reduces how much you need to borrow in the first place, and it moves you into a cheaper LTV band for the interest rate.

Where the crossover happens

Which cap binds depends on the relationship between income and property price, not on either number alone. Holding the property price and deposit percentage fixed and varying only income shows the crossover point directly.

Below roughly £62,000 of income in this example, the income multiple is the smaller number and limits the loan. Above that, the deposit cap takes over and the loan flattens at £266,000 – no matter how much higher income climbs, the loan can't exceed what a 95% LTV allows on a £280,000 property.

Why the deposit still matters even when it isn't the binding cap

Even in cases where the income cap is the one that limits the loan, a bigger deposit still helps, because UK mortgage rates are tiered by LTV band separately from the affordability caps. A lender might price a 60% LTV loan noticeably lower than a 95% LTV loan on otherwise identical terms, since the lender's risk is lower with more equity behind the loan. Moving from a 10% to a 15% deposit often shifts an application into a materially cheaper rate tier, even where it makes no difference to the maximum loan size.

Deposit sources lenders accept

Most lenders accept a deposit built from personal savings, the sale proceeds of an existing property, or a gifted deposit from a family member, provided the giver signs a declaration confirming it's a genuine gift, not a loan that has to be repaid. Some lenders also accept a deposit raised through a Lifetime ISA, which adds a 25% government bonus on savings contributions up to set annual limits, or through shared ownership and similar schemes with their own eligibility rules – checking a specific lender's accepted deposit sources before applying avoids delays late in the process.

• Personal savings: the most straightforward source, usually needing a paper trail of at least a few months' bank statements.
• Gifted deposit: accepted by most lenders with a signed gift declaration from the giver confirming no repayment obligation.
• Property sale proceeds: standard for anyone moving from an existing home, subject to that sale completing on time.
• Lifetime ISA and similar schemes: government-backed savings products with their own contribution limits and rules, separate from the mortgage application itself.