How Fees Compound Against You
A 1% fee sounds small. Over 30 years, it can take a quarter of your final pot.
Investment fees feel trivial because they're charged in tiny annual increments — 0.5% here, 0.25% there. But fees don't just take a slice of your gains. They take a slice of your compounded gains, year after year, on a balance that's growing. The mathematical effect is enormous.
The 30-year, 1% question
Imagine £100,000 invested for 30 years at 7% annual return:
• At 0.20% all-in fees → final pot ≈ £720,000
• At 1.00% all-in fees → final pot ≈ £574,000
• At 2.00% all-in fees → final pot ≈ £432,000
The 0.8% fee difference (between 0.2% and 1%) costs you £146,000 — over a quarter of the low-fee outcome — without a single year of underperformance.
Why it gets worse over time
Fees compound just like returns, but in reverse. Each year, the fee is charged on a higher balance. The pound amount grows. And every pound of fee removed is a pound that doesn't earn returns next year, and the year after, and so on.
Over 10 years, a 1% fee costs about 10% of your final pot. Over 30 years, it costs about 25%. Over 40 years, closer to 33%. The longer your horizon, the more fees matter.
The fees you're paying
UK investors typically pay several layers — see our full platform fee deep dive for the breakdown:
• Platform fee — 0% to 0.45%
• Fund / ETF fee (OCF) — 0.05% to 1.5%+
• FX fee — 0.15% to 1.5% per trade if buying foreign-listed
• Dealing fees — £0 to £12 per trade
• Advice fees — 0.5% to 1% if you use an IFA
An “active” managed fund charging 1.5% combined with a 0.45% platform sits at 1.95% all-in. A passive global ETF on a free platform sits at ~0.22% all-in. That gap, compounded for 30 years, is life-changing.
The simple optimisation
For most UK investors, the fee-minimising portfolio is:
1. A free or very cheap platform (Trading 212, InvestEngine, Vanguard, AJ Bell)
2. A globally-diversified index fund or ETF (0.10–0.25% OCF)
3. LSE-listed in GBP to avoid FX fees
4. Held in an ISA or SIPP to avoid tax
Total cost: ~0.15–0.30% per year. That's it. No advisor, no active fund, no clever overlay.
Quantify your own fee drag with the fund fee impact calculator — it shows the £ difference over your specific time horizon.
