How to start investing with your first £100

£100 won't make you rich. That's not the point of it. The point of a first £100 is to learn how investing works while the stakes are small enough that a bad week in the markets costs you the price of a takeaway, not a holiday.

This guide covers what to sort out before you start, what £100 can actually buy, the costs that matter most at this size, and the risks. It doesn't name any providers or funds, because the right one depends on you.

First, check you're ready

The Financial Conduct Authority, the UK's financial regulator, runs a campaign called InvestSmart. Its first rule is blunt: don't invest if you can't afford to. In practice, that means three things.

An emergency fund

Before you invest, have some cash you can get at quickly for a broken boiler or a lost job. The FCA notes that many experts suggest enough to cover three to six months of outgoings. It also says plainly: don't use your emergency fund to invest.

The reason is timing. Markets fall from time to time, and if you need the money during a fall, you have to sell at the low price. An emergency fund in a savings account means you never have to.

No expensive debt

If you're paying interest on a credit card or overdraft, paying that off is usually a better use of £100. The FCA puts it this way: the interest on most short-term debt is likely to be many times higher than the return on any investment. Clearing a debt is a guaranteed return. Investing isn't.

And never invest using a credit card. That's not a style choice; the FCA says it in so many words.

Time

Investing is for money you won't need for a while. The FCA suggests a timeframe of at least five years, which gives your investment more chance to ride out the dips. Money for a wedding next summer belongs in savings.

What £100 can buy

With £100 you could buy shares in one company. The trouble is that your whole £100 then rides on that one company. If it has a bad year, so do you.

The more common route is a fund. A fund pools money from lots of people and buys a wide spread of investments with it. The FCA says most people who invest choose funds that spread risk across many companies, industries and countries. Your £100 then owns a small slice of hundreds or thousands of companies, and one of them going bust is a rounding error rather than a disaster.

Spreading your money out like this is called diversification. In the FCA's words, it reduces your reliance on any one investment to perform.

Funds come in two broad flavours. Active funds pay a manager to try to beat the market, which the FCA notes isn't guaranteed. Tracker funds, also called index funds, just aim to match a market index, and their charges are typically lower. Our index funds guide goes into how they work.

Fees matter more when the amount is small

This is the bit most first-time investors miss. Investment platforms charge in different ways, and the way they charge can matter more than the fund you pick.

Some charge a percentage of what you hold each year. Others charge a flat fee, a fixed number of pounds a month. Funds have their own yearly charge on top.

Here's why that matters, with made-up numbers to show the shape of it. A flat fee of £4 a month is £48 a year. On a £100 pot, that's nearly half your money gone in a year, before the investments have done anything. On a £50,000 pot, the same £48 is barely noticeable. A percentage fee works the other way round: it stays small while the pot is small.

So with £100, look closely at how a platform charges, not just how much. The FCA warns that charges can mount up over time and eat into your returns. One of its five smart investment checks is simply: do I understand how this works, and what it costs?

Use the tax-free wrapper

A stocks and shares ISA is an account that holds investments. You don't pay tax on income or capital gains from investments in an ISA, and you can put up to £20,000 a year into ISAs in the 2026 to 2027 tax year.

On £100, the tax saving is close to nothing. Outside an ISA, you get a £500 dividend allowance each year before dividend tax is due. But if £100 turns into a habit, and the habit turns into a pot, having started in an ISA means you never have to think about it. Our stocks and shares ISA guide has the details.

Little and often

One £100 is a start. £100 a month is a plan. The FCA suggests committing to save regularly, perhaps every month right after payday, so the total builds up over time. Investing a fixed amount each month also means you buy a bit more when prices are low and a bit less when they're high, without having to guess which is which.

The FCA also notes that staying invested, rather than jumping in and out, helps keep costs low. The most expensive habit in investing is checking the app every day and acting on how you feel about it.

The risks, said plainly

The Financial Services Compensation Scheme protects investments up to £85,000 per person, per firm, but only in specific cases, like an authorised firm failing. The FSCS says it can't accept claims for poor investment performance. If the market falls, that's on you.

The FCA's last smart check is the one to sit with: what if my investment falls in value? If a 20% drop in your £100 would ruin your month, you're not ready yet. If it would just annoy you, you probably are.

And before you hand any money over, check the firm is authorised by the FCA. Anyone promising guaranteed high returns on £100 is selling something, and it isn't investing.

A first-£100 checklist

• Emergency fund in place, in a savings account you can get at.
• No credit card or overdraft debt you're paying interest on.
• Money you won't need for at least five years.
• A platform whose charges make sense for a small pot.
• A spread-out fund rather than one company's shares.
• A stocks and shares ISA to hold it in.
• A plan to add a bit each month, and to leave it alone.