The right amount to invest each month depends on your income, expenses, and goals. Here are realistic guidelines based on UK salaries, plus what each amount could grow to over time.
Several widely-used rules of thumb can help you work out how much to invest each month. None of them are perfect — personal circumstances vary enormously — but they provide a useful starting framework.
The 50/30/20 rule. This popular budgeting guideline suggests splitting your after-tax (net) income into three buckets: 50% on needs (rent, bills, food, transport), 30% on wants (entertainment, dining out, hobbies), and 20% on saving and investing. On a £30,000 salary (approximately £2,000 net per month), that 20% works out to £400 per month towards savings and investments combined.
The 15-20% rule for retirement. Many financial planners recommend directing 15-20% of your gross (pre-tax) income towards retirement savings, including employer pension contributions. On a £35,000 salary, 15% is £5,250 per year or approximately £437 per month. If your employer contributes 3% (£1,050), you need to find the remaining £4,200 (£350 per month) from your own contributions across your pension and ISA.
The "half your age" rule for pensions. Some pension experts suggest that the percentage of your salary you put into your pension should be at least half your age when you start. If you begin at 30, aim for 15%. If you start at 40, aim for 20%. This accounts for the reduced time for compounding when you start later.
The following table shows realistic monthly investment amounts at different UK salary levels, based on the 15-20% guideline. These amounts are in addition to your workplace pension contributions, which are handled separately through your employer.
| Annual salary | Monthly take-home (approx) | Comfortable range | Stretch target |
|---|---|---|---|
| £20,000 | ~£1,460 | £100–£150/mo | £200/mo |
| £25,000 | ~£1,700 | £150–£250/mo | £300/mo |
| £30,000 | ~£1,960 | £200–£300/mo | £400/mo |
| £40,000 | ~£2,540 | £300–£500/mo | £600/mo |
| £50,000 | ~£3,040 | £400–£700/mo | £900/mo |
| £60,000+ | ~£3,460+ | £500–£1,000+/mo | £1,200+/mo |
Take-home figures are approximate for a single person with no student loan, using 2025/26 tax bands. "Comfortable range" assumes 10-15% of take-home pay directed to ISA investing (on top of workplace pension). "Stretch target" assumes 15-20%. Your actual amount should reflect your personal expenses, debts, and goals.
The power of regular investing becomes clear when you project it forward. Here is what different monthly amounts could grow to over 25 years at 7% average annual returns in a tax-free ISA:
| Monthly amount | Total contributed | Projected value (25 yrs) | Growth from compounding |
|---|---|---|---|
| £50 | £15,000 | ~£40,500 | ~£25,500 |
| £100 | £30,000 | ~£81,000 | ~£51,000 |
| £200 | £60,000 | ~£162,000 | ~£102,000 |
| £300 | £90,000 | ~£243,000 | ~£153,000 |
| £500 | £150,000 | ~£405,000 | ~£255,000 |
| £1,000 | £300,000 | ~£810,000 | ~£510,000 |
Based on 7% average annual returns. All growth is tax-free inside an ISA. Past performance does not guarantee future results. Capital at risk when investing.
Notice how the compound growth column exceeds your total contributions in every scenario. At £300 per month, you contribute £90,000 of your own money over 25 years, but compound growth adds an additional £153,000 — that is £153,000 of wealth generated entirely by your money working for you. This is why consistency and time matter far more than the exact monthly amount.
Audit your subscriptions. The average UK household spends over £600 per year on subscriptions they rarely use — streaming services, gym memberships, apps, and magazines. Cancel anything you have not used in the last month. That is potentially £50 per month redirected to your investment account.
Track your spending for one month. Use your banking app or a spreadsheet to categorise every pound you spend. Most people are surprised by how much goes on impulse purchases, takeaway coffee, and convenience food. You do not need to eliminate these entirely — just identify where cuts are painless. Even saving £3 per day adds up to £90 per month.
Avoid lifestyle inflation. When you get a pay rise, direct at least half of the increase into your investments before adjusting your spending. If your salary goes up by £2,000, invest £1,000 more per year (£83 per month extra). You still get a pay rise, but your future self benefits enormously. Over a career with regular pay rises, this single habit can add tens of thousands of pounds to your investment pot.
Automate from payday. Set up a standing order to transfer your investment amount on the day you get paid. If the money leaves your current account before you have a chance to spend it, you will barely notice it is gone. This is the single most effective behaviour change for consistent investing.
A common mistake is waiting until you can "afford" to invest a large amount. In reality, starting small now almost always beats waiting. Here is a direct comparison:
Person A: starts now
~£52,100
£100/month for 25 years at 7%
Total contributed: £30,000
Person B: waits 5 years
~£52,100
£200/month for 20 years at 7%
Total contributed: £48,000
Person A and Person B end up with roughly the same amount — but Person A contributed £18,000 less of their own money. The extra 5 years of compounding compensated for the lower monthly amount. The lesson: start with whatever you can afford today. Time in the market is more powerful than the size of your monthly contribution.
Your investment amount does not need to stay fixed forever. In fact, gradually increasing it is one of the most effective strategies for building wealth. Here are practical approaches:
Match every pay rise. When your salary increases by 3%, increase your monthly investment by the same percentage. If you were investing £200 per month, bump it to £206. You will not notice the difference in your spending, but over a career, this adds up to significantly more wealth.
The £25 increment. Commit to increasing your monthly investment by £25 every six months or every year. Starting at £100, after 5 years you are investing £350 per month. This gradual escalation feels manageable and builds a much larger pot than keeping the amount static.
Windfall rule. Whenever you receive unexpected money — a tax refund, a birthday gift, a work bonus — invest at least 50% of it. These lump sums, invested early, have decades to compound and can make a disproportionate difference to your final pot.
Not all saving and investing is equal. There is a clear priority order that maximises the return on every pound:
1. Employer pension match. Always contribute enough to get the full employer match. If your employer matches up to 5%, contribute at least 5%. This is an instant 100% return — no other investment comes close. This should be your first priority, even before clearing debt (unless the debt interest rate is extremely high).
2. High-interest debt. Pay off any debt charging more than 5-6% interest — credit cards, store cards, personal loans. The guaranteed "return" of eliminating 20%+ credit card interest beats any investment return.
3. Emergency fund. Build 3 to 6 months of essential expenses in an easy-access savings account. This protects you from having to sell investments at a loss or take on debt when unexpected expenses arise. A high-interest savings account or premium bonds are ideal for this purpose.
4. Stocks & Shares ISA. Once your employer pension is matched, debt is cleared, and your emergency fund is in place, direct additional money into a Stocks & Shares ISA. The £20,000 annual allowance allows substantial tax-free growth. A global index fund is the simplest and most effective option for most people.
5. Additional pension contributions. If you have maximised your ISA and want to save more, consider increasing your workplace pension contributions (especially through salary sacrifice) or opening a SIPP. The tax relief on pension contributions is extremely valuable, particularly for higher-rate taxpayers.
See exactly how your monthly investments could grow with our free compound interest calculator.
Open compound interest calculatorReady to start investing? Trading 212 lets you begin with as little as £1 per month in a free Stocks & Shares ISA. Zero commission, fractional shares, and automatic monthly investing make it easy to build the habit. FCA regulated with FSCS protection up to £85,000.
Capital at risk. This is not financial advice. Affiliate link — we may earn a commission at no extra cost to you.
We value your privacy
We use cookies for analytics (Google Analytics) to understand how visitors use this site. No personal data is shared with advertisers. Read our Cookie Policy and Privacy Policy.