Best Low-Cost Investment Platform UK 2026/27

The lowest-cost UK platforms compared

What "low-cost" actually means

Investment cost has three layers: platform fee, fund/ETF OCF, dealing charges. A platform can be cheap on one layer and expensive on another. The number that matters is the total annual cost on your portfolio size.

InvestEngine at 0% platform fee only makes sense once you factor in the underlying ETF's OCF (0.05%–0.30% typical) — but even including that, it's usually the lowest total UK cost for a DIY ETF portfolio.

InvestEngine — the outright winner on cost for ETF portfolios

0% platform fee on DIY portfolios. 0% dealing on ETFs. Auto-invest and fractional ETFs supported. Regulated by the FCA (FRN 801128), FSCS investment cover applies.

You pay: the ETF's OCF (typically 0.10–0.25% for broad-market trackers), plus bid-ask spread when trading. That's it.

Reality check: "0%" doesn't mean "no cost". A well-chosen portfolio still costs 0.15%–0.25% all-in. But that's materially less than 0.45%+ elsewhere.

Open account with InvestEngine →

When Hargreaves Lansdown's fee cap wins

HL charges 0.45% on funds but caps custody at £45/year for shares and ETFs. On an ETF-only portfolio above about £10,000, HL's cost approaches InvestEngine's — and you gain HL's research library, phone support, and wider wrapper choice.

For an all-in cost of £45 platform + your ETF OCF, HL becomes an interesting choice if you value the extras.

Open account with Hargreaves Lansdown →

Interactive Investor — the flat-fee scenario

ii charges a flat monthly fee (£4.99–£12.99 depending on plan). For portfolios over ~£100,000, this becomes the cheapest option in percentage terms. Below that, InvestEngine's 0% usually wins.

Fee comparison across portfolio sizes

Assumes 100% in Vanguard FTSE All-World (OCF 0.22%). Excludes dealing and FX.

Decision framework — pick your low-cost platform

1. DIY ETF portfolio, any size? → InvestEngine (0% platform fee).
2. Portfolio over £100,000, want flat fee? → Interactive Investor.
3. Vanguard LifeStrategy specifically? → Vanguard Investor UK.
4. Want research + phone team + low ETF fees? → HL's £45 cap makes it competitive.

Hidden costs to watch

• FX charges on non-GBP-priced trades (Trading 212 0.15%; Freetrade 0.99% at free tier).
• Cash interest — platforms often keep some of the interest on uninvested cash.
• Fund entry/exit fees (dilution levies) — rare but exist on some UK funds.
• Regular investing discounts (HL £1.50 vs £11.95 headline).

Final recommendation

For a pure DIY ETF portfolio at any size, InvestEngine at 0% platform fee is the cost winner. For portfolios that value research and phone support alongside low ETF fees, Hargreaves Lansdown's capped £45/year on ETFs is genuinely competitive. Both are approved PennyWise partners.

Open account with InvestEngine →

Open account with Hargreaves Lansdown →

---

Frequently asked questions

Is 0% platform fee really 0?

Yes on InvestEngine DIY portfolios. You still pay the underlying ETF's OCF (set by the fund provider, not InvestEngine), typically 0.10–0.25%.

Does low cost mean lower quality?

Not necessarily. FSCS cover, nominee structure, and FCA regulation apply the same way. What you give up is research depth and (sometimes) phone support.

How much cost gap over 30 years?

On £20,000 at 6% growth, a 0.3% fee gap compounds to roughly £11,000 lost over 30 years. Small percentages matter.

Can I mix platforms?

Yes. Many UK investors hold ETFs on InvestEngine and funds/shares on HL. Just watch FSCS cover per platform (£85,000 per person).

What's the cheapest UK SIPP?

InvestEngine SIPP at 0% platform fee for DIY. See our best SIPP UK comparison.