UK House Deposit Time Calculator
See how long it will take to save your house deposit, and how much faster a Lifetime ISA's 25% government bonus can get you there.
Time to Reach Your Deposit
Target Deposit: £45,000
5 years, 1 month
What Is the UK House Deposit Time Calculator?
Working out how long it will realistically take to save a house deposit means combining your current savings, how much you can put away each month, and — for many UK first-time buyers — the 25% government bonus available through a Lifetime ISA. For every £4 you save into a Lifetime ISA, the government adds £1, up to £1,000 of free bonus per year on contributions up to £4,000. This calculator projects month by month how long it will take to reach your target deposit, with or without that bonus, plus simple interest growth on your balance.
The Lifetime ISA has one significant catch worth knowing before you rely on it: it can only be used toward a property costing £450,000 or less — a limit that hasn't changed since the scheme launched in 2017, even as average UK house prices have risen substantially since. This calculator checks your target house price against that cap and tells you directly if the bonus won't apply to your specific purchase.
UK House Deposit Time Calculator Formula
Target Deposit = House Price × Deposit %
Each Month: Balance += Contribution + LISA Bonus (25%, capped), then Balance ×= (1 + Interest Rate ÷ 12)
How Is the UK House Deposit Time Calculator Calculated?
This calculator simulates your savings balance month by month rather than using a single formula, since the Lifetime ISA bonus is capped annually (£4,000 of contributions per year, £1,000 of bonus) and interest compounds monthly. Each month, your contribution is added — split into a Lifetime ISA portion (up to roughly £333 per month, the £4,000 annual cap divided across the year) that receives the 25% bonus, and any remaining amount saved without a bonus — then monthly interest is applied to the full balance.
If a Lifetime ISA is selected but your target house price exceeds £450,000, this calculator switches automatically to a no-bonus projection and flags this clearly, since the bonus genuinely cannot be used toward that purchase under current rules, regardless of how much is saved into the account.
UK House Deposit Time Calculator Example
A £300,000 house with a 15% deposit (£45,000), starting from £5,000 saved, adding £500/month at 4% interest, using a Lifetime ISA: reaches the target in about 5 years, 1 month, with roughly £5,083 in free government bonus along the way.
The same scenario without a Lifetime ISA takes about 5 years, 9 months — 8 months slower, purely from missing out on the 25% bonus.
A £500,000 house with a 12% deposit (£60,000), starting from £10,000, adding £800/month: even with a Lifetime ISA selected, this property price is above the £450,000 cap, so no bonus applies — the projection uses regular savings growth only, reaching the target in about 4 years, 7 months.
How to Use the UK House Deposit Time Calculator
Step 1
Enter your target house price and the deposit percentage you're aiming for.
Step 2
Enter your current savings and how much you can save each month.
Step 3
Enter an expected savings interest rate.
Step 4
Toggle the Lifetime ISA option to see how much faster the 25% bonus could get you to your deposit.
Benefits
- Simulates real month-by-month growth, correctly handling the Lifetime ISA's annual contribution and bonus caps.
- Flags the £450,000 Lifetime ISA property price cap automatically, avoiding a false sense of eligibility.
- Shows the exact time saved and bonus received by using a Lifetime ISA versus regular savings.
- Uses verified current gov.uk Lifetime ISA rules.
- Free, instant, and runs entirely in your browser.
Common UK House Deposit Time Calculator Scenarios
Scenario 1
Planning a realistic house deposit savings timeline before starting to house-hunt.
Scenario 2
Deciding whether opening a Lifetime ISA is worth it for your specific savings plan and target property price.
Scenario 3
Comparing how a higher monthly contribution or a higher deposit percentage changes your timeline.
Scenario 4
Checking whether your target property price is compatible with using a Lifetime ISA before relying on the bonus.
Scenario 5
Setting a savings goal and monthly contribution target to hit a specific house-buying timeframe.
Understanding Your Result
The time shown is when your projected balance first reaches your target deposit, assuming consistent monthly contributions and steady interest growth — real savings rarely follow a perfectly straight line, so treat this as a realistic planning estimate rather than an exact date.
If a Lifetime ISA is eligible for your target property, the bonus meaningfully shortens your timeline for no extra effort beyond opening the account — it's widely considered one of the most straightforward ways for UK first-time buyers to boost deposit savings, precisely because the 25% return is guaranteed rather than dependent on investment performance.
Tips
- If your target property is near or above £450,000, check the price cap carefully before relying on Lifetime ISA growth in your plan — the bonus simply won't apply if you end up buying above that threshold.
- The Lifetime ISA must be open for at least 12 full months before funds can be used penalty-free toward a house purchase, so open the account as early as possible even if your first contributions are small.
- If you're buying with a partner who is also a first-time buyer, you can each hold a Lifetime ISA and combine both toward the same property, doubling the effective annual bonus cap for the household.
- This calculator assumes steady monthly contributions — a lump sum inheritance, bonus, or gift toward your deposit would shorten the timeline further than shown here.
- Withdrawing Lifetime ISA funds for anything other than a first home or after age 60 triggers a 25% government withdrawal charge, which can leave you with less than you paid in — this calculator assumes funds are used correctly for a first home purchase.
Common Mistakes
- Assuming the Lifetime ISA bonus applies to any property, without checking the £450,000 price cap first.
- Not opening a Lifetime ISA early enough to clear the 12-month minimum holding period before a planned purchase.
- Contributing more than £4,000 a year to a Lifetime ISA expecting bonus on the full amount — only the first £4,000 each year receives the 25% top-up.
- Forgetting that a Lifetime ISA is specifically for a first home — previous homeowners are not eligible to use it toward a purchase.
- Not accounting for interest or investment growth at all when estimating a savings timeline, understating how much monthly contributions alone will achieve.
Frequently Asked Questions
What is a Lifetime ISA?
A tax-free savings account for first-time buyers (or retirement saving) that adds a 25% government bonus on contributions up to £4,000 per year, worth up to £1,000 of free bonus annually.
Can I use a Lifetime ISA for any house price?
No — the property must cost £450,000 or less. This cap has been unchanged since the scheme launched in 2017, so it's worth checking carefully against current house prices in your target area.
How long does a Lifetime ISA need to be open before I can use it to buy a house?
At least 12 full months from account opening, so it's worth opening one as early as possible in your savings journey even before you have a specific property in mind.
Who is eligible to open a Lifetime ISA?
UK residents aged 18 to 39 can open an account, and can continue contributing (and receiving the bonus) up until age 50.
What happens if I withdraw Lifetime ISA funds for something other than a first home?
You'll face a 25% government withdrawal charge on the amount withdrawn, which can leave you with less than you originally paid in — the exception is withdrawing after age 60, or in cases of terminal illness.
Can two first-time buyers combine their Lifetime ISAs for one property?
Yes — if you're buying with a partner who is also a first-time buyer, you can each use your own Lifetime ISA toward the same property, effectively doubling the household's annual bonus potential.
Does this calculator account for house price growth while I'm saving?
No — it assumes your target house price and required deposit stay fixed throughout the savings period. If property prices in your target area are rising, you may need to revisit your target deposit periodically.
What interest rate should I use?
Use the actual rate offered by your savings account or Lifetime ISA provider — cash Lifetime ISAs and regular savings accounts vary, so check your specific provider's current rate rather than assuming a fixed figure.
Is a Lifetime ISA better than a Help to Buy ISA?
Help to Buy ISAs closed to new applicants in 2019, so a Lifetime ISA is now the primary government-backed first-time buyer savings scheme — existing Help to Buy ISA holders can still contribute to their existing account until November 2029.
Does the bonus get added immediately or at the end of the year?
In practice, HMRC typically pays the bonus monthly, about 4-8 weeks after each contribution, though this calculator simplifies the timing by applying the bonus in the same month as the contribution for a clearer projection.
What if I don't reach my target within 50 years in this calculator?
The calculator caps its projection at 50 years and shows "50+ years" — this typically means your monthly contribution is too low relative to your target deposit, and increasing it would meaningfully shorten a genuinely achievable timeline.
Can I share this savings projection as an image?
Yes — tap Share and, on supported devices, your result is shared as a branded image card, not just a text link.
References
Important Information
This calculator provides estimates for informational purposes only and is not financial advice. Uses confirmed current gov.uk Lifetime ISA rules (£4,000 annual contribution cap, 25% bonus, £450,000 property price cap, 12-month minimum holding period); assumes a fixed target deposit and steady contributions, and does not model house price growth during the savings period or variable interest rates. Confirm your specific eligibility and provider terms with HMRC or your Lifetime ISA provider.
Last updated: August 2026