How big a deposit do you actually need?
Everyone tells you to "save a deposit" and then goes quiet on the number. Here's what you actually need, and why the size you aim for matters more than people let on.
Reviewed 8 June 2026 · Information, not advice.
5% gets you in the door
Most lenders will take a 5% deposit. On a £250,000 flat that's £12,500. So if you've been told you need a fortune before you can even start, that's not true.
But 5% is the floor, not the goal. The bigger your deposit, the smaller your mortgage as a share of the price (lenders call this your loan-to-value, or LTV), and the lower your LTV, the cheaper the interest rate you're offered. That cheaper rate then runs for your whole fixed period, so a bigger deposit quietly saves you money every single month.
The numbers that actually move the needle
Rates tend to improve in steps, not smoothly. The big jumps are usually at 10%, 15% and 25% down. So if you're sitting on 8%, it's often worth holding on a bit longer to reach 10%, because the rate you unlock can save you more than the extra months of saving cost you.
Past about 25% down, the rate barely improves. At that point, throwing every last pound at the deposit isn't clever, it just leaves you moving in with no cushion. Keep something back for the fees and the surprise that always turns up in month one.
How to get there quicker
A Lifetime ISA is the closest thing to free money here: the government adds 25% on top of what you save, up to £1,000 a year. The catch is you have to open it at least a year before you buy, and it only works on homes up to £450,000.
Beyond that, a gift from family, the First Homes scheme and shared ownership can all shrink the deposit you need. None of them are free of trade-offs, but they're worth knowing about before you write off a whole area as out of reach.
Run your own numbers
Common questions
- Can I really buy with just 5% down?
- Yes. Plenty of lenders offer 95% mortgages, so 5% is enough to buy. You'll just pay a higher interest rate than someone with more behind them, which means a bigger monthly payment.
- Is a bigger deposit always worth it?
- Up to a point. More deposit means a cheaper rate and lower payments, but the gains flatten out above about 25%. Don't empty your account chasing them, keep a buffer for fees and moving in.
- Does my deposit cover the Stamp Duty and fees too?
- No, and this trips people up. Your deposit is separate from Stamp Duty, the solicitor, the survey and mortgage fees. Budget for those on top. Our cost-of-buying tool totals them up for you.