Half a million pounds is a genuinely life-changing sum. Under the 4% rule, a £500k portfolio can generate £20,000/year indefinitely — enough to cover basic living expenses for many people. At £500/month with 7% returns, reaching £500k takes approximately 28 years. With £750/month, you're there in about 25 years. Starting with a £50,000 inheritance or windfall and adding £400/month at 7%, you'd cross the half-million mark in roughly 25 years. What makes this target realistic is that the compound growth truly dominates in the later years: more than 60% of your final balance will come from interest, not contributions.
Illustrative estimate only — not a guarantee
~£623,213 after 28 years
£201,600 contributed + £421,613 interest
Based on a hypothetical constant return. Actual returns will vary.
By the CompoundWise Team · Updated April 2026
UK-based financial education · Not financial advice
Final Balance
£623,213
After 28 years
You Put In
£201,600
Your own money
Interest Earned
£421,613
Earned passively
You could reach £623,213 — investing tax-free can help you get there
To reach £623,213, most UK investors use a Stocks & Shares ISA to invest £600/month tax-free.
Returns depend on the underlying investments and are not guaranteed.
Your £600/month fits within the £20,000 ISA allowance
All growth inside an ISA is tax-free. Start from as little as £1.
Capital at risk when investing
Thousands of UK investors use this calculator monthlyAffiliate disclosure: Some links below are affiliate links. We may earn a commission at no extra cost to you if you sign up. This does not influence which platforms are shown or how they are described.
Many UK investors hold investments in a stocks & shares ISA for tax efficiency. Returns depend on the investments held within the ISA and are not guaranteed. Here are popular platforms available to UK investors.
| Platform | Min. invest | Fees | ISA | Best for |
|---|---|---|---|---|
| Trading 212 | Start from £1 | No commission | Yes | Beginner-friendly |
| Revolut | No minimum | Free plan available | Yes | All-in-one finance |
| Estateguru | Start from €50 | No investor fees | — | Property-backed lending |

Trading 212
Suited for: Beginner-friendly
Commission-free stocks & shares ISA. Clean app, no hidden charges, perfect for getting started.
Most popular choice for UK investors starting small
Revolut
Suited for: All-in-one finance
All-in-one finance app with savings vaults, stock trading, crypto, and multi-currency accounts. Great for everyday money management.

Estateguru
Suited for: Property-backed lending
European property-backed lending platform. Returns are not guaranteed and your capital is at risk. Past performance is not a reliable indicator of future results.
P2P lending is high risk. You could lose some or all of your money. Not covered by the FSCS.
Capital at risk. These are informational suggestions, not financial advice.
Invest from £1 tax-free
Capital at risk
Ready to start? Open a free ISA
Trading 212 · Start from £1 · No commission · FCA regulated
Saving £600 per month at 7% returns, your first year closes at approximately £7,452. By year five, your balance reaches roughly £41,800. The £100,000 milestone arrives around year 10 to 11, with your balance at approximately £104,400 and annual interest exceeding £6,600. By year 15, your portfolio reaches roughly £190,500, with compound growth contributing over £82,500. Year 20 brings approximately £313,000, and the final push to year 28 delivers roughly £500,000. In the last five years alone, your portfolio adds approximately £144,000 — driven predominantly by compound returns on your already substantial base. By the final year, your annual interest income exceeds £32,000, surpassing your annual contributions of £7,200 by more than four times.
Under the 4% withdrawal rule, a £500,000 portfolio sustains approximately £20,000 per year indefinitely — with a historically high probability of lasting 30 years or more. Combined with the full UK state pension (approximately £11,500 per year), this provides £31,500 annually. The Pensions and Lifetime Savings Association classifies a "moderate" retirement lifestyle at roughly £31,300 per year for a couple, meaning £500,000 plus state pension achieves exactly this level. This income covers regular holidays in Europe, a reasonable car, hobbies and leisure, and comfortable day-to-day living. For those targeting a "comfortable" retirement (approximately £43,100 for a couple), £500,000 would need to be supplemented by a workplace pension or additional savings.
A 28-year journey requires a robust, low-maintenance system. Open a stocks and shares ISA with a flat-fee platform (the most cost-effective choice once your portfolio exceeds £50,000 to £80,000). Invest your £600 per month in a globally diversified equity index fund — at this timeframe, equities offer the best growth potential despite short-term volatility. Automate your direct debit, enable dividend reinvestment, and set a calendar reminder for an annual review. During that review, check three things: is your fund still appropriate, can you increase contributions, and does your asset allocation still match your risk tolerance? As you approach the final five to eight years, consider gradually shifting 10% to 20% into bonds to protect your gains from a late-stage market downturn.
Increasing from £600 to £800 per month at 7% returns compresses the timeline to £500,000 from approximately 28 years to about 24 years — saving four years. Alternatively, at £800 per month for the full 28 years, you would reach approximately £674,000, providing £26,960 per year under the 4% rule. Reducing to £400 per month extends the timeline to roughly 34 years. The marginal value of each additional £100 per month at this level is approximately £60,000 over the full period — making even small increases highly worthwhile. If your income grows over time, a practical approach is to start at £600 and direct half of every future pay rise toward your investment, gradually increasing to £800 or £1,000 without any reduction in lifestyle spending.
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