How much deposit do I need for a mortgage?

For many home buyers, the deposit is one of the biggest upfront hurdles when planning a mortgage. The amount you need isn’t fixed—it depends on the property you’re buying, the mortgage product you’re considering, and how a lender assesses risk.

This guide explains what a deposit is, the deposit ranges commonly seen in the UK market, how deposit size links to loan-to-value (LTV), and what options may be available if you can’t reach a larger deposit.

Deposit basics: what “deposit” means

A mortgage deposit is the portion of the property price you pay upfront. The mortgage covers the remaining amount.

A simple way to picture it:

• Property price = what you’re buying the home for
• Deposit = what you pay now
• Mortgage amount = property price minus deposit

Because lenders price mortgages based on risk, the size of your deposit often influences:

• which mortgage products you can access
• the pricing tier you’re offered (including interest rate and fees)
• how strict the lender’s underwriting may be

Typical deposit ranges in the UK

While every lender has its own approach, many home buyers will see deposit options clustered around certain percentage bands.

0% deposit (sometimes via a guarantor arrangement)

In the UK, 100% mortgages are not typically available as a standard option. Where a 0% deposit route exists, it’s commonly structured through a guarantor.

A guarantor arrangement generally means a third party agrees to take on responsibility if repayments aren’t met. This additional support can make lending possible for buyers who can’t save a deposit, but it also means the guarantor’s finances are exposed to the outcome of the mortgage.

5% deposit (often the lowest mainstream starting point)

For many buyers, 5% is often discussed as a low deposit level in mainstream mortgage conversations.

Even if a low deposit is available, lenders will still look closely at other factors such as affordability, credit history, and the property itself.

10% deposit (a common benchmark)

A 10% deposit is often treated as a practical benchmark. At this level, many buyers find they have access to a wider range of mortgage products compared with very high-LTV borrowing.

20% deposit and above (often associated with better pricing tiers)

A 20% deposit is frequently mentioned because it can reduce the mortgage size relative to the property value, which may help with risk assessment.

In general terms, moving to a lower LTV position can improve the range of products available and may affect the cost of borrowing.

How deposit size affects your mortgage: LTV explained

Mortgage products are commonly described using LTV (loan-to-value).

What is LTV?

LTV compares the mortgage amount to the property value.

• LTV = mortgage ÷ property value

For example, if you buy for £250,000 and put down £25,000:

• mortgage amount = £225,000
• LTV = £225,000 ÷ £250,000 = 90%

Why LTV matters

Lenders often group mortgages into LTV bands. A higher LTV usually indicates higher risk, which can influence:

• the interest rate and fees you’re offered
• how strict the lender’s criteria are
• the likelihood of needing additional checks or documentation

How deposit is calculated (with examples)

Deposit is typically calculated as a percentage of the purchase price.

For a property costing £200,000:

• 5% deposit = £10,000
• 10% deposit = £20,000
• 20% deposit = £40,000

Even a relatively small change in deposit percentage can change the mortgage amount you borrow, which can affect both affordability and the mortgage products you may be able to consider.

Is there a “recommended” deposit?

There isn’t one universal deposit figure that suits everyone. The right deposit depends on balancing:

1. Affordability – what monthly payments you can comfortably manage
2. Mortgage cost – how interest rates and fees vary by LTV
3. Practical savings – how realistic it is to build a larger deposit within your timeline

For many buyers, the goal is to reach an LTV position that offers a sensible mix of affordability and mortgage options.

The financial impact of choosing a lower deposit

A smaller deposit can help you buy sooner, but it can also increase long-term costs. Key considerations include:

1) Mortgage pricing by LTV

Because lenders price by risk, higher-LTV borrowing can often mean higher interest rates or less favourable deal terms compared with lower-LTV borrowing.

2) Negative equity risk

If property values fall after you buy, it’s possible for the mortgage balance to be higher than the home’s value. This is known as negative equity.

A larger deposit reduces the mortgage size relative to the property value, which can lower this risk.

3) Flexibility later on

When you remortgage, your LTV at that time may be affected by:

• how much of the mortgage you’ve repaid
• changes in the property value
• changes in your circumstances and credit profile

Options if you can’t save a larger deposit

Saving more can be difficult, particularly when rent, bills, and everyday costs limit what you can put aside. Depending on your circumstances, some buyers consider alternative routes.

Shared ownership

Shared ownership can allow you to buy a share of a property while paying rent on the remaining share (typically owned by a housing association).

Because you’re buying only part of the property, the deposit is usually calculated on the value of the share you purchase. That can make the upfront deposit more manageable.

It’s important to understand the ongoing costs and how future share purchases may work.

Lifetime ISA (LISA)

A Lifetime ISA (LISA) may be used by eligible buyers to save towards their first home.

If you’re eligible, LISA savings can form part of your deposit plan, and the government bonus can help your savings grow. Rules and property eligibility can apply, so it’s worth checking the details before relying on a LISA.

Guarantor arrangements

If you’re exploring a 0% deposit route, a guarantor arrangement is one of the main structures that may make this possible.

This approach can help some buyers access lending, but it also places responsibility on the guarantor if repayments become difficult.

Putting it together: choosing the right deposit level

When deciding how much deposit to aim for, it can help to consider:

• Your timeline – whether waiting to save more is realistic
• Your monthly budget – ensuring payments remain affordable
• The LTV you’ll be working with – since this can affect product availability
• Whether alternative routes fit your situation (such as shared ownership or a LISA)

A low deposit can open the door to home ownership sooner, while a larger deposit can reduce the mortgage you borrow and may improve the range of mortgage options available.

Summary

• Deposit requirements vary by mortgage product and lender risk assessment.
• 0% deposit routes are often linked to guarantor arrangements.
• 5% deposits are often discussed as a low mainstream level.
• 10% is a common benchmark, and 20% is frequently discussed as a deposit level that can improve LTV positioning.
• LTV is central to how lenders structure mortgage options.
• If saving more is difficult, options such as shared ownership and Lifetime ISA may help some buyers.