Lifetime ISA maths

A Lifetime ISA adds 25% to everything you pay in, up to £4,000 a year, and charges 25% to take it back out for anything other than a first home under £450,000. Those two numbers do not cancel out, and that is the whole thing most people get wrong.

The three questions with a number in them

• What is the bonus on what I pay in? — 10 yearly amounts, ten years each.
• What does taking it out early cost? — 13 pot sizes, charge and net.
• Can I use it on this house? — 13 prices against the £450,000 cap.

The rule this site follows

No investment return is assumed anywhere. Every figure on every page is money you paid in plus the government bonus — the only part that is guaranteed. A site that shows you "your LISA at 60" has picked a growth rate out of the air and presented it as a fact; the arithmetic here stops where the guarantees stop.

Also here

• Lifetime ISA rules 2026/27 — age limits, holding period, what counts as a first-time buyer.
• The 2027 cash ISA change — what it does and does not do to a LISA.

Start here

• What the bonus is worth
• What early withdrawal costs
• The £450,000 property cap
• The rules in full
• The 2027 cash ISA change
• Paying in the £4,000 maximum
• Taking £10,000 out early

Rates and limits read 19 August 2026 from GOV.UK: Lifetime ISA, withdrawing money and ISA allowances. Figures are for the 2026/27 tax year.

Rates and limits for the 2026/27 tax year, read 19 August 2026 from GOV.UK. Nothing here is financial advice: it is arithmetic on published rules, and no investment return is assumed anywhere.