Investors who delay starting to invest until age 35 rather than age 25 can more than halve their eventual nest egg, according to Interactive Investor.
Fresh calculations from the investment platform reveal that waiting ten years to begin puts savers at risk of losing out on hundreds of thousands of pounds, trimming a final pot at age 65 by 58 per cent.
Holding back on contributions reduces the overall amount paid into an account and deprives the money of crucial time needed to compound and generate returns on top of previous returns.
For an investor putting away £100 a month starting at age 25, the projected pot reaches £404,642 by age 65. Delaying that initial start to age 35 reduces the expected final total to £171,077. Waiting another decade until age 45 causes the figure to drop to £65,828, which is almost 84 per cent less than starting two decades earlier.
The difference is even larger for higher monthly contributions. Someone putting aside £300 a month starting at age 25 can build a nest egg of £1.2 million by age 65. Delaying by ten years cuts that pot to £513,230, while waiting until age 45 leaves the saver with £197,485.
Assumptions and Market Risks
The platform's figures assume that monthly contributions increase by 2 per cent each year, in line with the Bank of England's annual inflation target, and that stock market investments deliver an average return of 8 per cent a year.
Investment returns on equities are historically higher than cash interest, though share values fluctuate and capital can be lost unlike guaranteed cash interest. In reality, returns could be better or worse than the predicted 8 per cent. Financial advice dictates that money should only be invested if it can be left untouched for at least five to ten years to absorb stock market fluctuations.
Camilla Esmund, head of investor campaigns at Interactive Investor, said: "Time in the market, not timing the market, is a classic investment mantra, and these calculations showcase just how true that is."
Esmund added: "These calculations show that the earliest investor is not just contributing for longer, they are also giving their money much more time to generate returns on top of previous returns. Starting earlier does not just add a few extra years of contributions, it gives investments more time to snowball."
She also cautioned against hesitation: "Building a well-diversified portfolio is indeed vital, and it's important that new investors understand this, but we should also remember that the hesitation of getting started in the first place could be costing you over the long term."
Understanding Compounding and Account Types
Compounding occurs when investment returns generate their own subsequent earnings, creating an accelerating growth curve over extended periods. The Bank of England sets monetary policy and the UK inflation target, which influences real purchasing power over multi-decade investment horizons.
UK retail investors typically use tax-efficient accounts to build long-term wealth. A Stocks and Shares ISA allows individuals to invest up to an annual allowance free from capital gains and income tax. A Self-Invested Personal Pension (SIPP) provides a personal pension framework with tax relief on contributions, while general investment accounts offer flexible access without contribution limits.
Comparing DIY Investment Platforms
Analysis from news outlet This is Money highlights that online DIY investing can be executed via mobile phone, tablet, or computer. Choosing an appropriate platform depends on administration charges, dealing fees, and the specific mix of funds, shares, and investment trusts offered by each provider.
Data compiled by This is Money in June 2026 compares the fee structures and features across major UK investment platforms:
AJ Bell: Charges a 0.25 per cent annual administration fee, capped at £3.50 per month for shares, trusts, and ETFs, and capped at £10 per month in a SIPP. Fund dealing costs £1.50, share and trust dealing is £5, regular investing is free, and dividend reinvestment costs £1.50 per deal.
Bestinvest: Levies a 0.40 per cent administration charge, which drops to 0.20 per cent for ready-made portfolios. Fund dealing is free, share dealing costs £4.95, regular investing is free for funds, and dividend reinvestment is free for income funds.
Charles Stanley Direct: Charges 0.30 per cent with a minimum fee of £60 and maximum of £600 per year, providing £100 back in free trades annually. Fund trades cost £4, share trades cost £10, and regular fund investing is free.
eToro: Offers free administration for stocks, investment trusts, and ETFs, though it provides a limited ISA and no SIPP. Fund dealing and regular investing are not available, while share dealing is free.
Fidelity: Charges 0.35 per cent on funds, structured as £7.50 a month for balances up to £25,000 or 0.35 per cent with a regular savings plan. Fund trades are free, share dealing is £7.50, regular investing is free for funds and £1.50 for shares, and dividend reinvestment costs £1.50.
Freetrade: Provides free account administration with access to stocks, funds, investment trusts, and ETFs, alongside optional paid plans. Fund and share dealing are free.
Hargreaves Lansdown: Charges a 0.35 per cent administration fee, capped at £150 annually for shares, trusts, and ETFs inside an ISA. Fund dealing is £1.95, share dealing costs £6.95, and both regular investing and dividend reinvestment are free.
Interactive Investor: Features a flat monthly administration fee of £5.99 for portfolios under £100,000 on its Core plan, rising to £14.99 on the Plus plan. The Plus plan includes one free trade per month. Fund dealing costs £3.99 on Core and £1.49 on Plus, share dealing is £3.99, regular investing is free, and dividend reinvestment costs £0.99.
InvestEngine: Offers free administration for ETF portfolios, charging 0.25 per cent for its managed service. Fund dealing is unavailable, while share dealing, regular investing, and dividend reinvestment are free.
Prosper: Offers free administration with refunded fees across 30 ETFs, but does not provide individual share trading. Fund dealing, ETF trading, regular investing, and dividend reinvestment are free.
Scottish Widows: Charges no administration fee. Fund and share dealing cost £5 per trade, while dividend reinvestment incurs a 2 per cent fee capped at £5.
Trading 212: Levies no administration fee for holding stocks, investment trusts, and ETFs. Share dealing, regular investing, and dividend reinvestment are free, though fund dealing is not available.
Vanguard: Charges a 0.15 per cent administration fee exclusively for Vanguard's own products and funds. Fund dealing is free for Vanguard funds, share dealing is free for Vanguard ETFs, and regular investing is free.
