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ISA Calculator 2026/27

Calculate tax-free growth on your Stocks & Shares ISA, Cash ISA or Lifetime ISA. £20,000 annual allowance. 25% LISA government bonus included.

✓ Last verified July 2026 — HMRC 2026/27 ISA allowances
⚡ Quick Answer

The ISA allowance for 2026/27 is £20,000 per person. Investing the full £20,000 annually at 7% average return (typical for a global stock market fund) for 20 years could grow to approximately £820,000 — completely tax-free. A Lifetime ISA adds a 25% government bonus (up to £1,000/year) for under-40s buying their first home or saving for retirement.

ISA Calculator — Select Your ISA Type
📈 Stocks & Shares
Invest in funds & shares
💰 Cash ISA
Fixed/variable interest
🏠 Lifetime ISA
25% govt bonus
£
Max £20,000/year (2026/27)
How long you'll invest
Stocks & Shares: 6–9% | Cash ISA: 4–5%
£
Current ISA pot (if any)
Total ISA Value
—
After — years
Tax-Free Growth
—
Investment returns
Total Contributions
—
Your money invested
Tax Saving vs Taxable
—
At 40% higher rate
Effective Annual Return
—
On total invested

💡 What This Means

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ISA Key Facts 2026/27

Annual Allowance
£20,000
Per person per tax year
LISA Allowance
£4,000
Within £20k total
LISA Govt Bonus
25%
Up to £1,000/year
Tax on Returns
Zero
No CGT, income tax, dividend tax
ISA Types
5 types
Cash, S&S, LISA, Junior, IFISA
Junior ISA
£9,000
Per child per year
ISA Growth Examples — £10,000/year at Different Returns
Investment Period3% (Cash ISA)5% (Balanced)7% (Stocks & Shares)9% (Growth)
5 years£54,684£57,191£60,153£63,359
10 years£118,078£132,068£148,363£167,519
15 years£191,295£228,322£275,903£335,925
20 years£275,615£359,929£479,841£642,974
25 years£372,646£528,863£773,491£1,184,985
30 years£484,374£748,726£1,202,476£2,124,499

Assumes £10,000 contributed at start of each year, returns compound annually, no withdrawals. All growth is tax-free inside an ISA.

ISA Types Comparison 2026/27
ISA TypeAnnual LimitWho Can UseBest ForWithdrawal
Cash ISA£20,00018+ UK residentsShort-term savings, emergency fundAnytime, no penalty
Stocks & Shares ISA£20,00018+ UK residentsLong-term wealth building (5+ years)Anytime, no penalty
Lifetime ISA (LISA)£4,00018–39 UK residentsFirst home or retirement (60+)Penalty if not for home/retirement
Junior ISA (JISA)£9,000Under 18 (opened by parent)Saving for childrenAt age 18 only
Innovative Finance ISA£20,00018+ UK residentsPeer-to-peer lendingDepends on platform

💡 ISA Tips — Make the Most of Your Allowance

1. Use Your Allowance Before 5 April Every Year

The ISA allowance resets on 6 April each year. Any unused allowance is lost — you cannot carry it forward. Invest early in the tax year to maximise compounding time, and make sure you've used this year's allowance before 5 April 2027.

2. Stocks & Shares ISA Beats Cash ISA Long-Term

Over any 15+ year period, a globally diversified stocks & shares ISA has historically returned 7–9% per year — far outpacing Cash ISA rates of 3–5%. For money you won't need for at least 5 years, the stocks & shares ISA is typically the better choice.

3. Open a LISA Before Age 40 for the Bonus

The Lifetime ISA gives a free 25% government bonus on up to £4,000/year — up to £1,000 free money per year. You must open it before your 40th birthday. If you're buying a first home or saving for retirement, the LISA bonus is one of the best free returns available.

4. Use Flexible ISA to Withdraw and Replace

Many Cash ISAs and some Stocks & Shares ISAs are "flexible" — meaning you can withdraw and replace money in the same tax year without using your annual allowance again. This gives you access to your savings without losing your ISA allowance for the year.

5. Open a Junior ISA for Children

The Junior ISA (JISA) allows you to save up to £9,000 per year tax-free for a child. The money is locked until the child turns 18, at which point it becomes their regular adult ISA. Starting early and investing in a stocks fund can build a significant sum by the time they need it for university or a first home.

6. Consider Both ISA and Pension

ISAs and pensions are complementary. Pensions give upfront tax relief on contributions (20–45%) but are taxed on withdrawal. ISAs give no upfront relief but withdrawals are 100% tax-free. A common strategy is to use pension for higher-rate tax relief and ISA for flexible, tax-free access to savings.

Frequently Asked Questions

What is the ISA allowance for 2026/27?
The ISA allowance for 2026/27 is £20,000 per person per tax year. This can be split across multiple ISA types. The Lifetime ISA has a separate £4,000 limit (which counts toward the £20,000 total). The Junior ISA allowance is £9,000 per child. Source: HMRC 2026/27.
How much will my ISA grow over 20 years?
Contributing £10,000/year to a Stocks & Shares ISA at 7% average annual return for 20 years could grow to approximately £480,000 — all tax-free. The full £20,000 allowance invested annually at 7% for 20 years could reach approximately £820,000. Actual returns will vary based on market performance.
What is a Lifetime ISA (LISA)?
A Lifetime ISA allows UK residents aged 18–39 to save up to £4,000 per year and receive a 25% government bonus (up to £1,000/year). The LISA can be used tax-free for a first home purchase (property up to £450,000) or for retirement from age 60. Withdrawals for other purposes incur a 25% penalty.
Is ISA growth tax-free?
Yes — completely. All returns inside an ISA are exempt from income tax, capital gains tax, and dividend tax. This applies indefinitely — there is no time limit on the tax-free status. You also do not need to declare ISA income or gains on your tax return.
Can I have multiple ISAs at the same time?
Yes — since April 2024, you can contribute to multiple ISAs of the same type in the same tax year. You can split your £20,000 allowance across as many Cash ISAs, Stocks & Shares ISAs, or other ISA types as you like. Your total contributions across all ISAs must not exceed £20,000 in one tax year.
Can I withdraw money from my ISA?
Yes, from a Cash ISA or Stocks & Shares ISA you can withdraw at any time without penalty or tax. With a flexible ISA, you can replace withdrawn amounts in the same tax year without using additional allowance. The Lifetime ISA is the exception — early withdrawals (not for first home or retirement) incur a 25% penalty.
What happens to my ISA when I die?
Your ISA loses its tax-free wrapper when you die, though the assets form part of your estate. Your spouse or civil partner can inherit an Additional Permitted Subscription (APS) equal to the value of your ISA — allowing them to shelter the same amount in their own ISA without using their annual allowance.

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Disclaimer: This calculator provides estimates for educational purposes only. Investment returns are not guaranteed. Always verify ISA rules at gov.uk or consult a qualified financial adviser. Last verified July 2026.