Quick answers
- What is an ISA? An Individual Savings Account. Money inside it grows free of UK income tax and capital gains tax.
- How much can you put in? £20,000 per tax year across all your ISAs combined (2026/27). The allowance resets each tax year — use it or lose it.
- Saving for a first home? A Lifetime ISA first, up to £4,000 a year, for the 25% government bonus.
- Saving for the long term (5+ years)? A Stocks and Shares ISA can grow more — but it can also fall. Never put deposit money you need soon into investments.
- Want zero risk? A Cash ISA. Your money is safe and earns interest, tax-free.
The one rule that governs all of them
You get a £20,000 ISA allowance each tax year. It covers everything you pay into Cash ISAs, Stocks and Shares ISAs, Lifetime ISAs and Innovative Finance ISAs combined. Your Lifetime ISA contributions count inside that £20,000 — so £4,000 into a LISA leaves £16,000 for everything else. When the tax year ends, unused allowance is gone. That does not mean rushing to fill it; it means planning across the year instead of discovering the limit in March.
Cash ISA — the safe one
You deposit cash, earn interest, pay no tax on the interest. In 2026, rates around 4–5% were available on cash ISAs, but rates move — check current ones before opening. Cash savings with a UK bank or building society are protected up to £85,000 per banking group under the Financial Services Compensation Scheme. Best for: emergency funds, and deposit money you will need within a couple of years.
Stocks and Shares ISA — the growth one
Your money buys funds, shares, or both. Over long periods (think 5 years or more), investments have historically grown more than cash — but they can fall, sometimes sharply, and there is no guarantee. Best for: money you will not need soon, where you can ride out falls. Worst for: a house deposit you need next year. A market dip just before you buy can wipe out more than a year of saving.
Lifetime ISA — the first-home one
The only ISA with a government bonus, and the only one with strict withdrawal rules:
- Open between ages 18 and 39; pay in up to £4,000 a year until you turn 50.
- Government adds 25% — up to £1,000 a year free.
- Use it for a first home costing £450,000 or less, bought with a mortgage, after the account has been open at least 12 months — or keep it for retirement from age 60.
- Withdraw for anything else and a 25% charge applies to the whole withdrawal, taking back the bonus and some of your own money.
Full detail, including the penalty arithmetic, is in the companion deposit guide (linked below). The £450,000 cap is the key check: if you plan to buy above it, especially in London and the South East, the LISA bonus is not available to you.
Which one fits your goal?
- First home within a few years, home under £450,000: Lifetime ISA up to £4,000 a year, then Cash ISA for the rest.
- First home, but above the £450,000 cap or unsure about buying: Cash ISA. No bonus, but no penalty trap either.
- Long-term wealth (5+ years, no fixed deadline): Stocks and Shares ISA, accepting the ups and downs.
- Emergency fund: Cash ISA, instant access, so the money is there when you need it.
- A mix: many people hold two — a LISA for the home and a Cash or Stocks and Shares ISA alongside it, inside the same £20,000 allowance.
Mistakes beginners make
- Putting deposit money into a Stocks and Shares ISA and needing it during a market fall.
- Paying into a Lifetime ISA while planning to buy above £450,000.
- Raiding a Lifetime ISA early and paying the 25% charge.
- Holding all savings in a current account earning nothing, when a Cash ISA would pay interest tax-free.
- Chasing the highest advertised rate without checking whether it is fixed, variable, or locked away for a year.
- Assuming the allowance carries over — it does not, but that is a reason to plan, not to panic-buy investments in March.
Read next
- How to Save for a House Deposit in the UK: The Complete 2026 Guide for First-Time Buyers
- First-Time Buyer Mortgage UK: Everything You Need to Know
- Credit Scores Decoded: How They Really Work in the UK
- How to Secure Funding for Your Business as a Young Founder
This article is general information, not financial advice. Allowances, rates and rules change — check GOV.UK and current provider terms before acting.
