House Deposit Saver Calculator
How to save for a house deposit — see exactly how long it will take to hit your target, how much a Lifetime ISA speeds things up, and what boosting your monthly saving could save you in time.
Estimate only. This is an illustrative projection, not a guarantee — savings rates change and this calculator assumes a constant rate throughout. Lifetime ISA rules, the £450,000 property price cap and age eligibility can change — always check the current rules on gov.uk. Not financial advice.
10% deposit on a £250,000 property
With vs without a Lifetime ISA
A Lifetime ISA gets you there 0 years, 5 months sooner.
Where your deposit comes from
| You save | £20,500 |
| Government bonus (LISA) | £3,000 |
| Interest earned | £1,809 |
| Deposit total | £25,309 |
Save a bit more, get there sooner
| Extra per month | New time to target | Time saved |
|---|---|---|
| +£50 | 3 years, 2 months | 0 years, 3 months |
| +£100 | 3 years, 0 months | 0 years, 5 months |
| +£200 | 2 years, 7 months | 0 years, 10 months |
How to save faster
- If you're a first-time buyer aged 18-39, a Lifetime ISA is usually the best place to start — the 25% government bonus is a guaranteed return you won't get anywhere else, on a home up to £450,000.
- Keep your deposit in its own separate savings account, away from everyday spending, so you're not tempted to dip into it.
- Set up a standing order to move your saving out on payday, before you see it land in your current account — "pay yourself first."
- A lodger (tax-free up to £7,500/year under the Rent a Room scheme) or a bit of side income can add hundreds a month without touching your main budget.
How this is worked out
We simulate your savings month by month, adding your monthly saving at the start of each month and then that month's interest on the resulting balance, for up to 40 years. If you switch on the Lifetime ISA option, the 25% government bonus is credited once a year on up to £4,000 of that year's contributions (a maximum of £1,000/year), and the bonus itself then earns interest too. The "with vs without LISA" comparison always runs both scenarios so you can see exactly how many months the bonus saves you.
A Lifetime ISA is for first-time buyers aged 18-39 buying a home worth £450,000 or less (or for retirement from age 60) — you can keep paying in until you're 50. Withdrawing for anything else triggers a 25% government penalty, which claws back more than just the bonus. Property price, deposit percentage, savings rate and monthly saving are all editable — this is a projection, not a guarantee, and real savings rates change over time.