ISA Calculator UK 2026
Compare tax-free ISA growth vs a taxable account — see exactly how much CGT and dividend tax you save
Use this free ISA calculator to see how your money grows tax-free inside a Stocks & Shares ISA or Cash ISA versus a standard taxable account. With CGT rates at 18–24% and dividend tax up to 35.75% from April 2026, the ISA wrapper saves most investors thousands of pounds over a typical investment horizon. Enter your details below to see your personal tax saving.
ISA Calculator — Frequently Asked Questions
What is the ISA allowance for 2026-27?
The annual ISA allowance is £20,000 for 2026-27, covering all ISA types combined (Cash ISA, Stocks & Shares ISA, Lifetime ISA, and Innovative Finance ISA). Unused allowance cannot be carried to the next tax year.
What is the difference between a Cash ISA and a Stocks & Shares ISA?
A Cash ISA holds money in savings accounts and earns interest tax-free. A Stocks & Shares ISA holds investments such as shares, funds, and bonds — any growth and income is completely tax-free. Stocks & Shares ISAs carry market risk but have historically delivered higher long-term returns.
How much CGT do I save with a Stocks & Shares ISA in 2026?
Outside an ISA, gains above the £3,000 annual exempt amount are taxed at 18% (basic rate) or 24% (higher rate) on shares and investments — rates that increased from October 2024. Inside an ISA all gains are permanently tax-free, regardless of size.
What are the dividend tax rates in 2026-27?
From April 2026, dividend tax rates increased to 10.75% (basic rate), 35.75% (higher rate), and 39.35% (additional rate). The dividend allowance is £500. All dividends received inside an ISA are tax-free.
Can I put £20,000 into a Cash ISA in 2026-27?
Yes — 2026-27 is the last tax year in which savers under 65 can put the full £20,000 into a Cash ISA. From 6 April 2027, savers under 65 will be limited to £12,000 per year in Cash ISAs (the overall £20,000 limit remains unchanged across all ISA types). Those aged 65 and over retain the full Cash ISA limit.
Can I open more than one ISA in the same tax year?
Yes. Since April 2024, you can open multiple ISAs of the same type in one tax year. However, your total contributions across all ISAs must not exceed the £20,000 annual allowance.
What is a Lifetime ISA and who should use it?
The Lifetime ISA (LISA) pays a 25% government bonus on contributions up to £4,000/year — up to £1,000 free per year. It is available to those aged 18–39 and can be used for a first home purchase (property up to £450,000) or retirement from age 60. Any other withdrawal incurs a 25% penalty.
Quick Tips
2026-27 Key Facts
- • Annual ISA allowance: £20,000
- • CGT exempt amount: £3,000
- • CGT on shares (basic rate): 18%
- • CGT on shares (higher rate): 24%
- • Dividend allowance: £500
- • Dividend tax (higher rate): 35.75%
ISA Types
- • Cash ISA — savings, tax-free interest
- • Stocks & Shares ISA — investments, tax-free growth
- • Lifetime ISA — 25% govt bonus, first home/retirement
- • Junior ISA — £9,000/yr for children
Note: From 6 April 2027, savers under 65 are limited to £12,000/yr in Cash ISAs.