ISA Allowance Calculator
Track your UK ISA allowance for 2026/27 across Cash, Stocks & Shares, Lifetime, and Innovative Finance ISAs. Project long-term tax-free growth.
The UK ISA allowance for 2026/27 is £20,000 per person per tax year, across all ISA types combined, Cash, Stocks & Shares, Innovative Finance, and Lifetime. Interest, dividends, and gains inside ISAs are tax-free forever. Unused allowance doesn't carry forward. Junior ISA allowance is £9,000 per child.
Track your contributions across accounts to stay within the £20,000 cap.
ISA Allowance Calculator
Max £4,000/year. 25% government bonus (up to £1,000/year).
£0
Total contributed
£20,000
Remaining
£0
LISA bonus (25%)
£4,000
LISA remaining
Long-Term Growth Projection
Projection assumes you contribute the same amount each year and all growth is reinvested. Returns are not guaranteed. Past performance doesn't predict future results. All ISA growth and income is tax-free, no income tax, CGT, or dividend tax.
ISA Types Comparison (2026/27)
| ISA Type | Annual Limit | Tax-Free | Best For |
|---|---|---|---|
| Cash ISA | £20,000* | Interest | Emergency fund, short-term savings, risk-averse savers |
| Stocks & Shares ISA | £20,000* | Gains + dividends | Long-term investing (5+ years), retirement pot |
| Lifetime ISA | £4,000 | Growth + 25% bonus | First home (under £450K) or retirement (after 60) |
| Innovative Finance ISA | £20,000* | Interest | P2P lending income (higher risk, higher return) |
| Junior ISA | £9,000 | Growth + interest | Long-term savings for children (locked until 18) |
*£20,000 is the combined total across Cash, Stocks & Shares, and IFISA. LISA's £4,000 counts within the £20,000. JISA has a separate £9,000 allowance.
How ISAs Work: The UK's Best Tax Shelter
An ISA (Individual Savings Account) is a tax-free wrapper around your savings or investments. Money inside an ISA grows completely free of income tax, Capital Gains Tax, and dividend tax. Outside an ISA, interest over your Personal Savings Allowance is taxed, share gains over £3,000 are taxed, and dividends over £500 are taxed. Inside an ISA, nothing. Zero. That's what makes them so valuable.
You get £20,000 of ISA allowance each tax year (6 April to 5 April). That might not sound like a lot, but it compounds: someone who maxes out their ISA every year for 20 years at 5% growth would have a pot worth roughly £694,000, all of it tax-free. The same investments outside an ISA could lose tens of thousands to CGT and dividend tax over that period.
Since April 2024, you can subscribe to multiple ISAs of the same type in the same year. Before that, you could only use one Cash ISA and one Stocks & Shares ISA per year. This change makes it easier to split savings across providers for better rates and diversification.
ISA vs Non-ISA: The Tax Difference Over Time
Here's the real-world impact of using an ISA vs a general investment account, assuming £10,000/year invested at 5% growth, 2% dividend yield, higher rate taxpayer.
| After | ISA Value | Non-ISA Value | Tax Saved |
|---|---|---|---|
| 5 years | £58,000 | £56,200 | £1,800 |
| 10 years | £132,000 | £124,500 | £7,500 |
| 20 years | £347,000 | £310,000 | £37,000 |
| 30 years | £694,000 | £592,000 | £102,000 |
| 40 years | £1,268,000 | £1,030,000 | £238,000 |
Illustrative figures assuming 5% capital growth + 2% dividend yield, higher rate taxpayer, CGT at 24%, dividend tax at 33.75%. Non-ISA assumes £3,000 CGT allowance and £500 dividend allowance used annually. Real returns will vary. The tax saving accelerates dramatically over time because compound growth amplifies the tax drag outside an ISA.
Lifetime ISA: Free Money (With Strings Attached)
£4,000
Annual contribution limit
Counts within your £20,000 ISA allowance. If you put £4,000 in a LISA, you have £16,000 left for other ISAs.
25% (up to £1,000/yr)
Government bonus
Paid monthly or annually depending on provider. Over a lifetime (age 18-50), you could receive up to £33,000 in bonuses alone.
£450,000
First home price cap
Property must be £450,000 or less. Must be your first property. Must use a mortgage (not cash purchase). Must have LISA open for 12+ months.
25% of total
Early withdrawal penalty
If you withdraw before 60 for non-qualifying reasons, you lose 25% of the withdrawal. This is more than the bonus, you lose 6.25% of your own money. Only withdraw early as a last resort.
Common ISA Mistakes
Letting your ISA allowance expire unused
The £20,000 allowance resets on 6 April and can't be carried forward. Even contributing a small amount is better than nothing, the tax-free wrapper is permanent. If you can't max out, prioritise Stocks & Shares ISA for long-term money and Cash ISA for emergency funds.
Holding cash in a Stocks & Shares ISA long-term
Many people open a S&S ISA, deposit cash, and never invest it. Uninvested cash in a S&S ISA typically earns near-zero interest. The whole point is to invest for growth. If you want to hold cash, use a Cash ISA (which pays actual savings interest). Check your platform, you might have forgotten to invest.
Withdrawing from a non-flexible ISA and expecting to re-contribute
With a non-flexible ISA, withdrawn money permanently reduces your allowance. If you put in £15,000 and withdraw £5,000, you can only add £5,000 more that year (not £10,000). Flexible ISAs let you re-contribute within the same tax year. Check your provider's flexibility before withdrawing.
Closing an old ISA to move the money instead of transferring
If you withdraw from an ISA and redeposit elsewhere, the money loses its ISA wrapper and uses your current year's allowance. Use the official ISA transfer process instead, the money moves between providers without losing tax-free status or using allowance. Your new provider initiates the transfer for you.
ISA Strategy by Life Stage
| Life Stage | Priority ISA | Strategy |
|---|---|---|
| Student / first job (18-25) | LISA + Cash ISA | Open a LISA immediately if you want to buy a first home. Use Cash ISA for emergency fund (3 months' expenses). Even small contributions start the 12-month LISA clock. |
| Building career (25-35) | S&S ISA + LISA | Maximise S&S ISA for long-term growth. Continue LISA for first home or retirement. Aim to build the ISA investing habit, even £200/month adds up. |
| Peak earning (35-55) | S&S ISA | Max out £20,000 if possible. Focus on low-cost index funds. This is when compound growth accelerates. Transfers from old ISAs to better platforms can improve returns. |
| Pre-retirement (55-65) | S&S ISA + Cash ISA | Gradually shift some ISA investments to Cash ISA for stability. Keep enough in S&S ISA to outpace inflation. Plan withdrawals to supplement pension income tax-free. |
| In retirement (65+) | Cash ISA + S&S ISA | Draw ISA income tax-free alongside pension. ISA withdrawals don't affect your State Pension or tax code. Preserve capital in Cash ISA, keep growth in S&S ISA. |
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Sources
- Gov.uk, Individual Savings Accounts (ISAs) 2026/27
- Gov.uk, Lifetime ISA rules and guidance
- HMRC, ISA manager guidance notes
- Gov.uk, Junior ISA allowance 2026/27
- FCA, ISA qualifying investments
- MoneyHelper, Choosing the right ISA
- Gov.uk, Changes to ISA subscription rules (April 2024)
How to use this tool
Enter how much you've contributed to each ISA type this tax year
See your remaining allowance, LISA bonus, and any over-subscription warnings
Set growth rate and time horizon to project long-term tax-free value
Common uses
- Tracking ISA allowance usage across multiple providers
- Calculating Lifetime ISA government bonus
- Projecting long-term Stocks & Shares ISA growth
- Planning ISA contribution strategy for the tax year
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