ISA Tax Planning

Key facts

The ISA allowance is £20,000 per person for 2026/27.
All growth, dividends, and interest within an ISA are completely tax-free.
You can split the £20,000 across different ISA types in the same year.
The Lifetime ISA has a separate £4,000 limit (counts towards the £20,000 total) with a 25% government bonus.
ISA allowances are use-it-or-lose-it — they cannot be carried forward.

Why ISAs Matter for Tax Planning

Individual Savings Accounts (ISAs) allow you to save and invest up to £20,000 per year completely free of Income Tax and Capital Gains Tax. Unlike pensions, there is no tax to pay when you withdraw the money, making ISAs one of the most flexible tax shelters available.^[1]

Types of ISA

ISA Type	Allowance	Best For
Cash ISA	Up to £20,000	Risk-free savings; emergency fund
Stocks & Shares ISA	Up to £20,000	Long-term investment; growth
Innovative Finance ISA	Up to £20,000	Peer-to-peer lending
Lifetime ISA	Up to £4,000 (counts towards £20,000)	First home or retirement (age 18–39)

You can split the £20,000 across multiple types. For example, you could put £4,000 in a Lifetime ISA and £16,000 in a Stocks & Shares ISA.^[1]

Tax Benefits of ISAs

No Income Tax on interest or dividends received within the ISA
No Capital Gains Tax on profits when you sell investments inside the ISA
No tax on withdrawal — take your money out at any time, tax-free
ISA income does not count towards tax thresholds (personal savings allowance, dividend allowance, or High Income Child Benefit charge)

Tip: If you are a higher-rate taxpayer receiving dividends outside an ISA, you pay 35.75% on dividends above the £500 allowance. Inside an ISA, the same dividends are completely tax-free — a saving of £357.50 on every £1,000 of dividends.

The Lifetime ISA

The Lifetime ISA (LISA) has special rules:^[2]

Available to those aged 18–39 (you can keep contributing until age 50)
Maximum contribution: £4,000 per year
Government adds a 25% bonus (up to £1,000 per year)
Withdrawals for a first home (up to £450,000) or after age 60 are penalty-free
Other withdrawals incur a 25% penalty on the amount withdrawn (which claws back more than just the bonus)

ISA Planning Strategies

Bed & ISA

A “bed & ISA” involves selling investments held outside an ISA and immediately repurchasing them inside your ISA. This crystallises any gain (potentially using your £3,000 CGT annual exemption) and shelters future growth from tax. See our article on using your CGT annual exemption for more detail.

Couples Strategy

Each individual has their own £20,000 ISA allowance. A married couple or civil partners can collectively shelter £40,000 per year. Over 10 years, that could build a £400,000+ tax-free investment portfolio.

Annual Discipline

Because ISA allowances cannot be carried forward, the key is to contribute each year — even if only a small amount. Setting up a monthly direct debit into a Stocks & Shares ISA also benefits from pound-cost averaging.

ISA vs Pension compared: For a 40% taxpayer investing £10,000 of gross income — a pension contribution of £10,000 costs £6,000 after tax relief, but withdrawals are taxed. An ISA contribution of £6,000 (from post-tax income) grows and is withdrawn completely tax-free. The best strategy usually involves using both.

Frequently Asked Questions

Can I have more than one ISA?

Yes. From April 2024, you can open and pay into multiple ISAs of the same type in the same tax year (previously you could only pay into one of each type). Your total contributions across all ISAs must not exceed £20,000 in the tax year.

Is an ISA better than a pension?

They serve different purposes. Pensions offer upfront tax relief (20%–45%) but you pay Income Tax when you withdraw (after a 25% tax-free lump sum). ISAs have no upfront relief but withdrawals are completely tax-free. Most advisers recommend using both where possible.

What happens to my ISA when I die?

Your ISA loses its tax-free status on death, but your spouse or civil partner can inherit an additional ISA allowance equal to the value of your ISA at the date of death (the Additional Permitted Subscription, or APS).

Can I withdraw from an ISA and put the money back?

With a “flexible ISA” you can withdraw and replace funds in the same tax year without using up extra allowance. Not all ISAs offer this feature — check with your provider.

Sources

Individual Savings Accounts (ISAs) — GOV.UK
Lifetime ISA — GOV.UK
ISA manager guidance — HMRC