Interactive Investor
Interactive Investor pioneered the flat-fee model in the UK — you pay the same monthly fee regardless of pot size. At £11.99/month (Investor plan), the annual cost is £143.88 whether your pot is £10,000 or £1,000,000. This makes ii dramatically cheaper than percentage-fee platforms for larger pots: on a £500,000 pot, ii costs £144/year vs Hargreaves Lansdown's £1,750. The breakeven point vs Vanguard is around £100,000 — below that, Vanguard's 0.15% is cheaper; above it, ii's flat fee wins. ii offers the same breadth of investment choice as HL (3,000+ funds, shares, ETFs) but at a fraction of the cost for bigger portfolios. The main drawback is that for very small pots (under £25,000), the flat fee represents a higher effective percentage than cheaper platforms.
- +Flat fee regardless of pot size — best value for large pots
- +Wide investment choice (3,000+ funds, shares)
- +Free regular investing
- +Good research tools
- –Flat fee is expensive on small pots (effective 0.6% on £25k)
- –Dealing charges on ad-hoc trades (£3.99-£5.99)
- –Multiple plan tiers can be confusing
- •Fees shown are platform fees only — you also pay fund-level charges (OCF) on top, which vary by fund choice.
- •Fee structures change without notice. Always verify the current fee on the provider's website before making any decision.
- •The cheapest provider is not necessarily the best fit — consider fund range, customer service, platform features, and the specific funds you want to hold.
- •Transferring a pension may involve exit fees, loss of guaranteed benefits, or loss of employer contributions. Check before you transfer.
- •This page is factual information based on published fee schedules, not a recommendation to use or avoid any provider.
- •If you're unsure which provider is right for you, speak to an FCA-regulated financial adviser.
This calculator provides estimates based on 2025/26 tax rates and is not financial advice. Scottish taxpayers are subject to different income tax rates and bands. The calculations assume your salary is your only source of income and do not account for benefits in kind or other taxable income.
For personalised guidance on your pension contributions, speak to an FCA-regulated financial adviser. You can find one via Unbiased or VouchedFor.