How much to invest to reach £1 million?
At a typical long-term return, around £820 a month for 30 years gets you to £1 million. But the real lever isn’t the amount — it’s time. Start earlier and the monthly figure tumbles.
The short answer
Assuming a 7% average annual return, reaching £1 million takes roughly £820 a month over 30 years. Stretch to 40 years and it drops to about £381 a month; squeeze it into 20 years and it jumps to around £1,920. The single biggest factor isn’t how much you invest — it’s how early you start, because compounding does the heavy lifting.
A million pounds sounds like a number for other people. Run the maths, though, and it’s mostly a function of two things: time, and consistency. Not income, not luck, not picking the right stock.
Here’s why. Money invested compounds — your returns earn returns — and over decades that snowball does far more work than your contributions. Someone investing £381 a month for 40 years puts in about £183,000 of their own money. The other £817,000 comes from growth.
That’s the whole game. The earlier you start, the more years compounding has to work, and the less you personally have to put in. Which is why the monthly figure swings so wildly with your timeframe.
Why starting early beats investing more
Compare two people, both aiming for £1 million at 7%. Start at 25 with 40 years to run and you need about £381 a month. Wait until 35, with 30 years left, and it’s £820 — more than double, for starting just ten years later.
The uncomfortable truth: the person who starts at 25 and stops at 35 often ends up ahead of the person who starts at 35 and pays in for thirty years — despite investing for a quarter of the time. That’s compounding rewarding time over effort.
A reality check on the 7%: that’s a long-run average for global shares before inflation, and returns are never guaranteed — some years are great, some are negative. A million in 30 years also won’t buy what a million buys today. Treat the figure as a planning guide, not a promise, and invest tax-efficiently through an ISA or pension so the taxman doesn’t take a slice of the growth.
What changes the monthly figure?
Three levers move how much you need each month — and they’re not equally powerful.
!How early you start
By far the biggest lever. Each extra decade of compounding roughly halves the monthly amount needed. Time beats money.
%The return you assume
A higher average return needs smaller contributions — but you can’t control returns, and chasing them adds risk. 7% is a common long-run planning figure.
£Your starting lump sum
Already have savings to invest? A lump sum at the start compounds for the full period, cutting the monthly top-up needed to reach the target.
Monthly investment to reach £1 million
What you’d need to invest each month at a 7% average annual return, by how long you have. Starting from zero, no lump sum.
| Years invested | Monthly investment | Your own contributions |
|---|---|---|
| 20 years | £1,920 | ~£461,000 |
| 25 years | £1,234 | ~£370,000 |
| 30 years | £820 | ~£295,000 |
| 35 years | £555 | ~£233,000 |
| 40 years | £381 | ~£183,000 |
Look at the last column: over 40 years you personally contribute under £183,000, and compounding supplies the other £817,000. Over 20 years you put in £461,000 — far more of your own money — for the same £1 million. That gap is the value of starting early. Model your own timeline with the compound interest calculator.
The million-pound path, worked through
One realistic example, to show how time and tax wrappers shape the number.
- The timeframe. Jordan has 35 years until 65 — a long runway for compounding.
- The monthly figure. At 7%, reaching £1M over 35 years takes about £555 a month.
- The wrapper. Jordan invests through a Stocks & Shares ISA and a pension, so growth and withdrawals are sheltered from tax.
- The contribution. Over 35 years that’s roughly £233,000 of Jordan’s own money — the other £767,000 is growth.
- The discipline. Jordan automates the £555 and leaves it alone through market ups and downs, resisting the urge to time it.
The takeaway: Jordan’s million is three-quarters compounding, one-quarter contributions — and that ratio only works because of the 35-year runway. Had Jordan started at 45 with 20 years left, the same target would demand nearly £1,920 a month.
Find your own monthly figure
Enter your timeframe and expected return to see what reaching £1 million — or any target — takes each month.
Investing for a million questions, answered
How much do I need to invest to become a millionaire?
Can I become a millionaire by investing £500 a month?
Is 7% a realistic investment return?
Why does starting early matter so much?
Where should I invest to reach £1 million?
How much of a £1 million pot is my own money?
Should I invest a lump sum or monthly?
Related guides & tools
How this guide is built
Monthly figures are calculated with standard compound-interest maths at a 7% average annual return, from a zero starting balance. Returns are illustrative and not guaranteed; real returns vary and inflation erodes future purchasing power. ISA and pension rules follow current GOV.UK guidance.
Definitions and sources: methodology · sources.
Not financial advice. This guide is for general information and links to calculators that produce estimates. Investments can fall as well as rise and returns aren’t guaranteed — consider regulated financial advice before investing.