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UK Help to Buy ISA Calculator

Free UK Help to Buy ISA calculator. Closed to new accounts in 2019, existing accounts compute pot and 25 percent government bonus.

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Project Help to Buy ISA pot + 25% bonus.

Total available on completion

Your savings

Government bonus (25%)

Your breakdown

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A legacy account that still pays out until 2030

The Help to Buy ISA shut to new savers on 30 November 2019, but if you opened one before then it remains live and the government bonus is still on the table until 1 December 2030. That deadline matters, because the bonus is not paid as you go. It is claimed by your conveyancer at the point you complete on your first home, and if you let the account drift without buying, you eventually forfeit the top-up. This calculator projects where your pot lands by completion and how large the 25 percent bonus will be when your solicitor applies for it.

The contribution rules baked into the numbers

Two limits shape every Help to Buy ISA. You could pay in up to £1,200 in the first month and then £200 a month afterwards, and the government bonus is 25 percent of your savings, capped at £3,000. To collect the full £3,000 you need £12,000 of your own money in the account. There is also a minimum: the bonus only kicks in once you have saved at least £1,600, producing a £400 bonus floor. The tool enforces the £200 monthly ceiling so your projection stays realistic.

Two more years of saving on a £3,000 balance

Take the defaults. You already hold £3,000 and keep paying the maximum £200 a month for another 24 months, adding £4,800. Your own savings reach £7,800. The bonus is 25 percent of that, which is £1,950, comfortably under the £3,000 ceiling. Your conveyancer claims it at completion and you walk to the purchase with £9,750.

Where the Lifetime ISA pulls ahead

If you have any meaningful time left before you buy, the Lifetime ISA is usually the stronger account, and the difference is structural. The Help to Buy bonus is capped at £3,000 forever, and the property price ceiling is £250,000, or £450,000 inside London. The Lifetime ISA lets you pay in £4,000 a year, pays a 25 percent bonus of up to £1,000 every year with no lifetime cap, and works on homes up to £450,000 anywhere in the country. Over several years a Lifetime ISA can deliver far more than £3,000. You cannot pay into both for the same home purchase in the same tax year and claim both bonuses, so most savers with a longer runway transfer across. One sharp edge to know: the Help to Buy bonus cannot be used towards the exchange deposit, only the completion funds, which occasionally surprises first-time buyers who assumed it would cover their 10 percent on exchange day.

Who should keep their Help to Buy ISA open

This tool is for existing holders working out whether their pot will clear the £3,000 ceiling and when to stop paying in. If you are within a year of buying, the convenience and the locked-in bonus may outweigh switching. A practical tip: once you have hit £12,000 of savings, further contributions earn no extra bonus, so that money usually works harder in a Stocks and Shares ISA or a higher-rate savings account. Keep an eye on the December 2030 cut-off, because an unclaimed bonus on a stalled account is simply lost.

Can I hold a Help to Buy ISA and a Lifetime ISA at the same time?

You can hold both, but you may only put the government bonus from one of them towards the same first-home purchase. Many savers keep paying into the Lifetime ISA for its larger bonus and treat the old Help to Buy balance as a cash reserve, transferring it in where the rules allow.

What happens to the bonus if I decide not to buy?

You keep all your own savings and any interest, and you can withdraw them with no penalty at any time. You simply do not receive the 25 percent government bonus, because that is only ever paid when you complete on a qualifying first home.

Frequently asked questions

Help to Buy vs Lifetime ISA?
Help to Buy is legacy (closed to new accounts 2019, deadline to claim bonus 2030). LISA is the current first-home government bonus scheme: £4K/year cap, 25 percent bonus up to £1K/year. LISA is strictly better for new savers.
What is the maximum government bonus I can receive?
The government bonus is 25 percent of your own savings, capped at £3,000. To receive the full £3,000 bonus you need at least £12,000 of your own contributions in the account. There is also a minimum threshold: you must have saved at least £1,600 to qualify for any bonus at all.
When is the deadline to claim the Help to Buy ISA bonus?
You must complete your first home purchase on or before 1 December 2030 to claim the bonus. After that date, the scheme closes entirely, and any unclaimed bonus is forfeited. Your solicitor or conveyancer submits the claim at completion, not at exchange.
Can I use the Help to Buy ISA bonus for the exchange deposit?
No. The government bonus is paid at completion, not at exchange. This is a common source of confusion for first-time buyers who assume the bonus will cover their 10 percent exchange deposit. You will need to fund the exchange deposit from other savings and then receive the bonus when you legally complete on the property.

Related calculators

Sources

  1. HMRC — Income Tax Rates and Personal Allowances 2026/27, HM Revenue & Customs
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