10% is standard; 5% via Help to Buy / FTB products.
A decent easy-access or LISA rate (UK LISA adds 25% government bonus).
What is a mortgage deposit?
A mortgage deposit is the cash you pay towards the purchase price. The loan covers the rest. A 10% deposit is a common target for a standard residential mortgage. A larger deposit usually means a lower interest rate, because you are borrowing a smaller share of the property value.
First-time buyers under 40 can use a Lifetime ISA. The government adds 25% to eligible savings, on top of any interest the account pays. This calculator compounds monthly, so you can see how long a target takes at the amount you save and the rate you expect. It does not include stamp duty or legal fees, which you also need in cash at completion.
Saving £500/month, you'll reach a £30,000 UK mortgage deposit in 3y 9m.
How to reach your deposit faster
Use a LISA (under-40s)
Save up to £4,000/year into a Lifetime ISA and get a 25% government bonus — effectively +£1,000/year free. Must be used for a first home under £450,000 or pensions.
Optimise cash savings
Easy-access savings regularly beat 4% AER. Fixed-rate savings accounts can add another 0.5–1% if you can lock up cash for 1–3 years.
Frequently asked questions
How much deposit do I need for a UK mortgage?
Most UK lenders accept a 10% deposit. First-time buyers can sometimes get 5% products. 15–25% unlocks sharper rates. Buy-to-let usually requires 25%+.
What's the best savings account for a deposit?
Under-40s: a Lifetime ISA (LISA) gives a 25% government bonus on up to £4,000/year — best-in-class for FTB deposits. Otherwise a high-yield easy-access or fixed-rate savings account.
Does this calculator factor in house-price growth?
No — the target is fixed. If UK house prices rise faster than your contributions, your timeline extends. Consider setting a slightly higher target to account for inflation.
Should I invest instead of saving cash?
If your deposit is 3+ years away, a stocks & shares ISA can outpace cash — but with short-term volatility risk. For <3 years, stick with cash or LISA cash.
Can parents help with the deposit?
Yes — gifted deposits from immediate family are accepted by most lenders. Some also accept loans from family (treated as monthly outgoings). A Joint Borrower Sole Proprietor mortgage adds a parent's income without them being on the deeds.
Reviewed by the Mortgage118 editorial team. House-price growth not modelled. This calculator provides an estimate only and does not constitute financial advice.
- Compounding
- Monthly
- Contribution timing
- End of month
- Price growth
- Not modelled
Consider a LISA for under-40s — 25% government bonus on up to £4k/yr.