Stocks & Shares ISA Calculator

Explore the long-term power of tax-free investing with our Stocks & Shares ISA calculator. Fully updated for the current tax year.

Stocks & Shares ISAs: A Smart Way to Grow Your Money Tax-Free

If you’re serious about building long-term wealth, a Stocks & Shares ISA is one of the most powerful tools available to UK investors.

It’s a tax-efficient investment account that lets you grow your money in the stock market — without paying Income Tax or Capital Gains Tax on your returns.
In other words: your profits stay yours.

You can invest up to £20,000 per tax year (2025/26 limit). That allowance renews every April, giving you a fresh chance to make the most of it.

How Stocks & Shares ISA’s Work

When you open a Stocks & Shares ISA, you can invest in:

Individual company shares
Exchange-traded funds (ETFs)
Investment trusts
Ready-made portfolios or managed funds

Over time, your investments can rise (and sometimes fall) in value, depending on how the market performs.
The key is to stay invested for the long term, ideally five years or more, so short-term ups and downs have time to smooth out.

Why Starting Early Really Matters

Time is the most valuable asset any investor has.

If you start investing in your 20s, your money has decades to benefit from compound growth (the process of earning returns on your returns).

For example:
If you invest £200 a month for 30 years at an average annual growth rate of 5%, you could end up with around £167,000.
Wait ten years to start, and you’d have less than £90,000.

That’s the power of compounding and why starting early can make such a big difference.

Fees: What You’ll Pay (and Why It Matters)

Every investment platform charges some form of fee, and over time those charges can have a huge impact on your returns.

Here’s what to look out for:

Platform fee: Usually between 0.15% and 0.45% per year of your portfolio value
Fund or ETF costs (OCFs): Typically 0.06% to 0.25% per year
Dealing fees: Some charge per trade, while others are free for funds or ETFs

It might not sound like much, but even a 1% fee difference can cost tens of thousands of pounds over a few decades.

Always check the small print before opening an account.

Choosing the Right Platform

Your ideal ISA provider depends on how hands-on you want to be.

Platform Type	Example Providers	Best For
Low-cost app-based brokers	Freetrade, Trading 212, InvestEngine	New investors who want simple, low-fee investing
Full-service platforms	AJ Bell, Hargreaves Lansdown, Fidelity	Investors who want more choice and detailed research tools
Robo-investors	Nutmeg, Moneyfarm, Wealthify	Hands-off investors who prefer automated portfolios

Before signing up, think about:

How much you’ll invest each month
Whether you prefer to pick your own funds or use ready-made portfolios
The type of customer support and educational tools you might need

🔍 Tip: If you’re just starting out, focus on low fees and simplicity. You can always move your ISA to a different provider later if your needs change.

Why It’s Especially Important for Young Investors

For younger investors, time is your superpower.
Even small, regular contributions can grow into something meaningful over the years.

By starting early:

You give compounding time to work in your favour
You can take a longer-term view, riding out market dips
You build healthy money habits early on

Investing isn’t about chasing quick wins, it’s about being consistent and letting time do the heavy lifting.

Use the Calculator Above to See What’s Possible

Want to see how your own investments could grow?
Use our Stocks & Shares ISA calculator above to test different scenarios.

Try adjusting your monthly contribution, investment term, and growth rate.
You’ll instantly see how your projected ISA balance changes and how small tweaks can make a big long-term difference.

A Quick Reality Check

A Stocks & Shares ISA is designed for medium-to-long-term investing.
The value of your investments can fall as well as rise, and there’s no guarantee you’ll get back the amount you put in.
However, history shows that staying invested and diversifying typically leads to better outcomes over time.

Start small. Stay consistent. Let time and compounding do the rest.
Because the sooner you begin, the more your future self will thank you.