How Much Deposit Do I Need for a Mortgage? A First-Time Buyer's Guide

For most first-time buyers, the deposit is where hesitation sets in before anything else. Before affordability checks, before credit scores, before viewing a single property, there's the question of how much deposit you need for a mortgage and whether what you've saved is actually enough. If you haven't looked at the basics of applying for a mortgage yet, our general guide is a good place to start. 

This one goes deeper on the deposit itself.

The Minimum vs. the Realistic Figure

Technically, you can get a mortgage with a 5% deposit. On a £250,000 property, that's £12,500, often less than people assume. But there's a difference between the minimum you need and what most buyers actually put down: the average deposit among UK first-time buyers currently sits closer to 15–20% of the purchase price.

Neither figure is right or wrong. With 10–15% or more, you open up a noticeably wider range of products and rates, and you're less exposed if property values dip shortly after you buy. But the minimum exists for a reason too, it depends on your circumstances, your timeline and how much you can realistically build without delaying your purchase for years. The right answer often becomes clear only once you sit down with an adviser and see what different deposit levels change for you, both in monthly cost and in which lenders are willing to work with your situation. Self-employed applicants, or anyone with a less-than-perfect credit history, may also find some lenders ask for a slightly larger deposit to offset the additional risk on their side.

How Your Deposit Affects Your Rate

Your deposit size determines your Loan-to-Value ratio, or LTV, the proportion of the property's value you're borrowing rather than putting down yourself. A 5% deposit means a 95% LTV mortgage; a 15% deposit brings that down to 85%.

The lower your LTV, the more competitively lenders tend to price your mortgage, and the more products become available to you. This is one of the main reasons why how much deposit you need for a mortgage isn't a single fixed number, it shifts depending on what rate and flexibility you're chasing, not just what you can scrape together.

Gifted Deposits: What Lenders Need to See

Many first-time buyers rely on help from family, and lenders are generally comfortable with this, but they need proof of where the money has come from. A parent, grandparent or other close family member gifting funds will usually need to provide a gifted deposit letter confirming the money is a genuine gift, not a loan, and that they have no stake in the property.

Lenders also carry out source-of-funds checks as standard anti-money-laundering practice, so be prepared to show a paper trail: bank statements and savings history, or documentation of how the gifting relative obtained the funds. It can feel intrusive, but it's routine, and a good adviser will tell you exactly what's needed before it becomes a delay.

When Family Wants to Help Beyond a Gift

Sometimes a straightforward gift isn't possible, or isn't enough on its own. Guarantor mortgages and Joint Borrower Sole Proprietor (JBSP) arrangements are two ways family can support a purchase without simply handing over cash. A guarantor mortgage uses a family member's income or assets as security, while a JBSP mortgage adds a parent to the mortgage itself, sharing responsibility for repayments, without adding them to the property's title.

Both come with trade-offs worth understanding upfront. A guarantor typically needs to demonstrate they can cover the mortgage alongside their own commitments if required, and their own borrowing capacity may be affected while the arrangement is in place. JBSP mortgages are offered by a smaller pool of lenders and assessed using combined income, which can open up borrowing that wouldn't otherwise be possible. But it also means the added party carries real financial responsibility, not just a supporting role on paper. 

These are more specialist arrangements, and not every lender offers them. Fowler Smith has real experience navigating this area, from working out which lenders will consider them to structuring the affordability case properly from the outset.

Low-Deposit Schemes Worth Knowing About

If 5% is genuinely where you're starting from, the Mortgage Guarantee Scheme (also known as Freedom to Buy) is worth knowing about. Now a permanent government-backed scheme, it supports 95% mortgages on properties up to £600,000, for both first-time buyers and home movers, on a repayment basis. 

It's only available for a residential home you intend to live in, and it doesn't lend you money directly, it gives participating lenders confidence to offer higher-LTV mortgages they might otherwise avoid.

The First Homes scheme works differently and is worth knowing about too: eligible first-time buyers can purchase certain new-build properties in England at a discount of at least 30% below market value. This reduces the amount you need to borrow and the deposit required in cash terms, since it's a fixed percentage of a lower price. 

Shared ownership is another route some buyers overlook, you buy a share of a property and pay rent on the rest, meaning your deposit is based only on the share you're purchasing rather than the full price.

Building Your Deposit Faster

A Lifetime ISA remains one of the most effective tools available: save up to £4,000 a year and receive a 25% government bonus, usable toward a first home up to £450,000. Reform of the LISA is currently under government consultation, so it's worth checking the latest position before relying on it long-term.

Beyond that, the basics still matter most: a dedicated savings account separate from everyday spending, with transfers set up automatically on payday so saving happens before you have the chance to spend it. 

It's also worth an honest look at whether overpaying rent to move faster is really a better trade-off than building a bigger deposit steadily. Small, consistent amounts add up faster than people expect, especially when a bonus or tax refund goes straight into savings rather than everyday spending.

Ready to Talk Through Your Deposit?

Whether you're working with 5% or more, gifted funds, a guarantor, or a JBSP arrangement, the right next step depends on your situation. If you haven't seen it already, our full guide to applying for a mortgage covers what happens next. Get in touch with Fowler Smith's team for a no-obligation conversation about where you stand.

FAQs

How much deposit do I need for a mortgage?

As a minimum, the deposit you need for a mortgage typically comes down to 5% of the property price, though 10–15% or more generally unlocks more suitable rates and a wider choice of lenders.

Can I use a gifted deposit for my mortgage?

Yes. Most lenders accept gifted deposits from close family, provided you can supply a gifted deposit letter and evidence of where the funds came from.

What is a Joint Borrower Sole Proprietor mortgage?

It's a mortgage where a family member shares responsibility for repayments without being named on the property's title, a way to boost affordability without adding them as an owner.