Best index funds for Junior ISAs: a beginner's guide

You've opened a stocks and shares Junior ISA for your child. Now comes the question that stops a lot of parents in their tracks: which fund should the money actually go into? There are thousands to choose from.

The good news is that it can be very simple. For many families, one low-cost global index fund does the whole job. This guide explains what index funds are, why low costs matter so much, and compares five well-known funds.

The short answer: a single global index fund, such as the Vanguard FTSE Global All Cap Index Fund or the Fidelity Index World Fund, spreads your child's money across well over a thousand companies around the world for a small yearly charge. Pick one, set up a regular payment, and leave it to grow.

Fund charges and platform fees change, so check the current figures on the fund's factsheet and your provider's price list before you invest. The charges below were correct to the best of our knowledge in September 2026.

See what regular payments could grow to with our Junior ISA calculator.

What are index funds, and why do they matter?

Index funds in plain English

An index fund follows a market index, such as the FTSE 100 or the S&P 500, by owning the companies in that index.

How they work:

• The fund buys shares in the companies in the index
• When the index changes (companies join or leave), the fund follows
• Your money is spread across hundreds or thousands of companies straight away
• Charges are low, often between 0.05% and 0.25% a year

Example: a FTSE 100 index fund owns shares in the 100 largest UK companies. When the FTSE 100 goes up 5%, the fund goes up by about 5%, less its small charge.

Why index funds suit Junior ISAs

Active funds pay a manager to try to "beat the market" by picking companies. That sounds appealing, but:

• Most active funds do worse than their index over 15 years or more, once charges are taken off
• Their charges are higher, often 0.7% to 1.5% a year
• Results depend on the manager, who can move on or have a bad run
• They're harder to understand

Index funds, by contrast:

• Follow the market, up and down, for a small charge
• Spread money across whole markets automatically
• Are simple to explain: "we own a little bit of the world's companies"

Charges matter more than they look. Here's £200 a month for 18 years, assuming 6% a year before charges (an illustration, not a promise):

• With 0.15% a year in charges: about £75,400
• With 1.00% a year in charges: about £69,300
• Difference: about £6,100, just from charges

Our Junior ISA providers guide covers the other half of the cost: the platform fee.

Five well-known low-cost index funds

These are examples of widely available, low-cost funds, not the only good ones. Squids-In is independent, and we don't earn anything from any fund or provider we mention. Most large platforms offer them or close equivalents. When buying, search by name and check you've got the accumulation version (often shown as "Acc"), which reinvests dividends for you.

1. Vanguard FTSE Global All Cap Index Fund

What it holds: over 7,000 companies in around 50 countries: large, medium and small, in developed and emerging markets.

Fund charge: 0.23% a year, plus your platform's fee.

Where the money goes (roughly):

• USA: about 62%
• Europe excluding the UK: about 11%
• Japan: about 6%
• UK: about 3%
• Emerging markets: about 10%
• Rest of the world: the remainder

What's good about it:

• One fund covers almost the whole world's stock market
• Includes smaller companies as well as the giants
• Includes emerging markets such as India and Brazil
• Nothing to rebalance

Worth knowing:

• The charge is higher than some similar funds (0.23% against 0.12% to 0.13%)
• It follows the world market, so the USA is a large share

In short: about as simple and complete as it gets. One fund, done.

2. Fidelity Index World Fund

What it holds: about 1,300 large and medium-sized companies in developed countries (the MSCI World index). No emerging markets.

Fund charge: 0.12% a year, plus your platform's fee.

Where the money goes (roughly):

• USA: just over 70%
• Europe excluding the UK: about 12%
• Japan: about 6%
• UK: about 3%
• Other developed countries: the remainder

What's good about it:

• One of the cheapest global funds available
• Covers all the major developed markets

Worth knowing:

• Leaves out emerging markets (such as China, India and Brazil)
• Leaves out smaller companies
• An even bigger share in the USA than an all-world fund

In short: a very low-cost choice if you're happy with developed markets only. Over 18 years at £200 a month, its lower charge might add up to around £800 more than the Global All Cap, before platform fees. Some people think emerging markets are worth including; others don't mind leaving them out. Both are reasonable views.

3. HSBC FTSE All-World Index Fund

What it holds: about 3,400 large and medium-sized companies in developed and emerging markets. (The index it follows has about 4,200; the fund holds a representative sample.)

Fund charge: 0.13% a year, plus your platform's fee.

Where the money goes (roughly):

• USA: about 60%
• Japan: about 6%
• UK: about 3%
• Emerging markets such as China and Taiwan: a few per cent each
• Rest of the world: the remainder

What's good about it:

• Almost as cheap as the Fidelity fund
• Includes emerging markets

Worth knowing:

• Leaves out smaller companies, unlike the Global All Cap

In short: a middle way: emerging markets included, at a very low charge.

4. Vanguard FTSE UK All Share Index Unit Trust

What it holds: about 540 UK companies of all sizes.

Fund charge: 0.06% a year, plus your platform's fee.

What's good about it:

• Very low charge
• Many large UK companies earn much of their money abroad

Worth knowing:

• It's just one country, which is about 3% of the world's stock market
• On its own, it's much less spread out than a global fund

In short: better as a small extra alongside a global fund than as the only holding.

5. An S&P 500 index fund

Several providers offer one, including Vanguard, Fidelity, HSBC and iShares.

What it holds: the 500 largest US companies.

Charges: around 0.06% to 0.07% a year for the big providers' versions, plus your platform's fee.

What's good about it:

• Very low charges
• US companies have done especially well in recent years

Worth knowing:

• It's just one country, however big
• No UK, Europe, Asia or emerging markets
• Its value moves with the pound-dollar exchange rate
• Strong recent years don't tell you what comes next

In short: a global fund already puts around 60 to 70% in the USA. An S&P 500 fund on its own is a narrower bet on one country.

Simple ways to put it together

The one-fund approach

One fund:

• 100% in a global index fund (such as the Vanguard Global All Cap, Fidelity Index World or HSBC All-World)

Why it works:

• Thousands of companies in one go
• Nothing to rebalance
• No decisions to make

Suits: families who want it simple and low-maintenance. This is what many families do.

The lowest-cost approach

One fund:

• 100% in the Fidelity Index World Fund (or a similar developed-world fund)

Why it works:

• Very low charges
• Covers all developed markets

The trade-off: no emerging markets. Some see that as less bumpy; others as missing part of the world.

Global plus a little UK

Two funds:

• 70% global index fund
• 30% UK All Share fund

Why some families do it:

• A tilt towards UK companies
• More of the money in pounds

Worth knowing: you'll need to rebalance now and then, and the global fund already includes UK companies. It adds a bit of complexity for not much difference.

Three funds, including bonds

Three funds:

• 60% global index fund
• 20% UK All Share fund
• 20% global bond index fund

Why some people do it:

• Bonds make the ride smoother
• More control over where the money goes

Worth knowing: bonds reduce ups and downs, but usually reduce long-term growth too. With 18 years or more ahead, many families keep a child's Junior ISA entirely in shares, and only think about bonds or cash if the money will be needed soon.

Our stocks and shares vs cash comparison goes into why a long time frame matters.

Questions to help you choose

1. How simple do you want it?

As simple as possible: → One global index fund

Simple, with the lowest charges: → One developed-world fund, such as Fidelity Index World

Happy to hold two or three funds: → A global fund with a UK or bond fund alongside

2. Which platform are you using?

Not every platform offers every fund, and platform fees differ a lot. Some charge a percentage, some a flat fee, and some charge nothing on Junior ISAs. Look at the fund charge and the platform fee together. Our providers guide compares some of the main ones.

3. Do you want emerging markets?

Yes, the whole world: → Vanguard FTSE Global All Cap or HSBC FTSE All-World

Developed markets are fine: → Fidelity Index World

Not sure: → Emerging markets are about 10% of an all-world fund, so the difference either way is modest.

Common mistakes

1. Too many funds

The problem: buying 10 or 15 funds in the belief that more is safer.

In practice: one global index fund already owns thousands of companies. More funds mostly means overlap, more to keep track of and sometimes higher charges.

Instead: start with one global fund. Add another only for a clear reason.

2. Chasing last year's winners

The problem: choosing funds from "best performers of the last three years" lists.

In practice: past performance doesn't predict future returns. Last year's winner is often next year's disappointment.

Instead: choose on spread, charges and simplicity, not recent charts.

3. Paying more than you need to

The problem: an active fund charging 1.2% a year when an index fund covering the same market charges 0.12%.

In practice: on £200 a month for 18 years at 6% before charges, that difference could cost around £7,700.

Instead: start from low-cost index funds, and only pay more for a good reason.

4. Only UK companies

The problem: putting everything in UK funds because UK companies feel familiar.

In practice: the UK is about 3% of the world's stock market, so an all-UK portfolio is very concentrated.

Instead: use a global fund as the core, with a UK tilt if you'd like one.

5. Trying to time the market

The problem: waiting for the "right moment" to invest, or selling when markets fall.

In practice: some of the market's best days have come soon after its worst. Miss a handful of them and long-term returns can be much lower.

Instead: invest regularly and let the ups and downs pass.

Our guide to teaching kids about compound interest explains why staying invested matters.

The funds side by side

Charges as of September 2026, from each fund manager's own factsheet.

Platform fees come on top. All five are low-cost; the bigger decision is how much of the world you want to own.

What the charge could mean over 18 years

Example: £200 a month for 18 years, 6% a year before charges (an illustration only). Fund charges as of September 2026.

What stands out: the differences between low-cost index funds are small. The gap to a typical active fund is much bigger.

Different funds will also grow by different amounts, depending on which markets do well, so treat this as a comparison of charges only.

When might an active fund make sense?

Some families do choose active funds. It might make sense if:

• You have ethical or religious requirements that index funds don't meet
• You enjoy researching fund managers and following how they do
• You've found a fund with a long, strong record and reasonable charges
• You understand you're relying on a manager, and you're comfortable with that

Index funds tend to suit you if:

• You want it simple
• You're investing for 10 years or more
• You'd like low costs
• You'd rather spend the time with your family than researching funds

Setting it up

Step 1: log in to your Junior ISA provider

Step 2: find the fund

Search by name. Check the factsheet to make sure it's the right fund, and pick the accumulation version, which reinvests dividends automatically.

Step 3: decide how to pay in

Options:

• A one-off lump sum
• A regular monthly payment by direct debit
• Both

Many families find a monthly direct debit easiest: it builds a habit, and buying a little each month means sometimes buying when prices are lower.

Step 4: confirm, then leave it alone

A sensible routine:

• Look once or twice a year, not every week
• Rebalance if you hold more than one fund
• Pay in more when you can
• Otherwise, leave it be

Checking often doesn't improve returns. It mostly tempts people into selling after a fall.

Helping your child understand what they own

Explanations for different ages

Ages 5-9: "We're buying tiny pieces of lots of companies around the world. If those companies grow, your money grows too."

Ages 10-14: "This fund owns small parts of thousands of companies, including big names you'd recognise. When those companies make more money over the years, what you own tends to be worth more."

Ages 15-17: "You own a global index fund that follows the world's stock markets. Over long periods it has grown with company profits, though it goes down as well as up, and there are no guarantees."

Tools that help

Rather than showing them a spreadsheet:

• The Time Machine in the Squids-In app shows what time could do to their savings
• Our Junior ISA calculator projects regular payments
• Short lessons can explain index funds, spreading risk and compound growth

Squids-In has 130 short lessons for children aged 10 and up, including what index funds are and why spreading risk helps. In the Island Market game, they can try picking made-up companies with pretend money, and see how they do against a steady fund.

Common questions

Q: Can I change funds later?

A: Yes. You can sell one fund and buy another inside the Junior ISA at any time, with no tax to pay. Most platforms let you do it online. Switching often rarely helps, though, and may cost dealing fees.

Q: What if I'd rather avoid tobacco, weapons or fossil fuel companies?

A: Broad index funds include every industry. If that's a concern, look at ESG (environmental, social and governance) or faith-based index funds, which leave out certain sectors while staying spread out. Their charges are often a little higher.

Q: What's the difference between accumulation and income versions?

A: Accumulation (Acc) reinvests dividends back into the fund. Income (Inc) pays them into your account as cash. For a Junior ISA, accumulation is usually simplest, so nothing sits idle.

Q: Do I need to rebalance?

A: With one fund, no. With several (say 70% global and 30% UK), check once a year. If one has grown faster and the split is now 80/20, move some back to return to 70/30.

Q: Should I change anything as my child gets closer to 18?

A: Some families gradually move towards cash in the last two or three years, if the money will be needed at 18. Others stay invested, because the Junior ISA becomes an adult ISA and the money doesn't have to come out. It depends on whether your child is likely to need it straight away.

Q: What if the fund closes or merges?

A: It's rare for large index funds. If it happens, your provider will tell you and usually move you to a similar fund or hold the money as cash inside the Junior ISA. You don't lose the money or the tax benefits.

Key points

• For many families, one global index fund is enough: simple, spread out and low-cost
• Vanguard FTSE Global All Cap (0.23%), Fidelity Index World (0.12%) and HSBC FTSE All-World (0.13%) are well-known low-cost examples
• Most active funds do worse than their index over the long run, once charges are taken off
• Charges add up: the gap between an index fund and a typical active fund can be thousands of pounds over 18 years
• More funds isn't more spread: one global fund already owns thousands of companies
• Choose the accumulation version so dividends are reinvested
• Pay in regularly and leave it alone: time in the market beats timing the market
• Help your child understand what they own

Our guide to opening a Junior ISA walks through the rest of the process.

Next steps

1. Pick an approach: one global fund is the simplest
2. Choose the fund, and check its current charge on the factsheet
3. Log in to your Junior ISA platform
4. Search for the fund by name
5. Choose the accumulation version
6. Set up a monthly direct debit, if that suits you
7. Confirm
8. Look once or twice a year, and otherwise leave it alone

Don't get stuck choosing. The difference between two good low-cost global funds is small. The difference between starting now and waiting six months to decide is usually bigger.

See what regular payments could become with our Junior ISA calculator.

Frequently asked questions

Can you buy index funds for a child?

Yes. A child can't hold funds in their own name, so a parent or guardian opens a Junior ISA (or a bare trust) and chooses the investments inside it. The account is in the child's name and becomes theirs at 18. From 16, the child can take control of how it's invested. Most Junior ISA platforms offer the same index funds available to adults.

Are index funds a good choice for children?

Index funds suit long time frames, and a child's money may be invested for 18 years or more. They spread money across hundreds or thousands of companies, cost very little to hold, and need no ongoing decisions. The trade-off is that they follow the market down as well as up, so the value will fall in some years.

Which Junior ISA providers offer low-cost index funds?

Most large UK platforms do. What matters more than the provider is the total cost: the platform fee plus the fund's ongoing charge. Some platforms charge a flat annual fee, others a percentage, so the cheapest option depends on how much you invest. Compare both figures rather than either alone. Our Junior ISA providers comparison walks through the differences.

What is the difference between an index fund and an ETF in a Junior ISA?

Both track an index. An ETF trades on an exchange like a share, so it may carry dealing charges each time you buy; an index fund is priced once a day and is often free to buy on platforms that support regular investing. For small monthly payments into a Junior ISA, the dealing costs usually matter more than the difference in structure.

How many funds does a Junior ISA need?

One global index fund already spreads money across thousands of companies in dozens of countries, so holding several funds often adds overlap rather than diversification. More funds also means more to rebalance and more to get wrong.

Saving for the very long term too? A Junior SIPP locks money away until pension age (57 at the earliest under current rules), and gets a 25% government top-up. Our Junior SIPP calculator shows what monthly payments could become by retirement.

Related guides:

• Junior ISA providers compared
• How to open a Junior ISA
• Stocks and shares or cash Junior ISA
• What is a Junior ISA?

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This article is for education only and isn't financial advice. Fund charges change, so check current figures before investing. The value of investments can go down as well as up, and past performance doesn't guarantee future returns.