If you want to pick your own shares and ETFs, the cheapest ISA depends on three things: how often you trade, how big your portfolio is, and whether you buy US shares. Here’s what each platform costs in each case.
All figures come from our fee calculator, using each platform’s published charges. They cover the account fee and dealing charges but not FX fees, which we compare separately below.
Annual cost: 12 trades a year
A typical investor buying shares or ETFs once a month, placing each trade manually:
| Platform | £10k | £25k | £50k | £100k | £250k |
|---|---|---|---|---|---|
| Trading 212 | £0 | £0 | £0 | £0 | £0 |
| Freetrade (Basic) | £0 | £0 | £0 | £0 | £0 |
| Dodl | £15 | £38 | £75 | £150 | £375 |
| Barclays | £72 | £72 | £72 | £72 | £72 |
| AJ Bell | £85 | £102 | £102 | £102 | £102 |
| Interactive Investor | £120 | £120 | £120 | £120 | £180 |
| Fidelity | £180 | £180 | £180 | £180 | £180 |
| Hargreaves Lansdown | £118 | £171 | £233 | £233 | £233 |
Annual cost: 4 trades a year
A buy-and-hold investor adding a lump sum once a quarter:
| Platform | £10k | £25k | £50k | £100k | £250k |
|---|---|---|---|---|---|
| Trading 212 | £0 | £0 | £0 | £0 | £0 |
| Freetrade (Basic) | £0 | £0 | £0 | £0 | £0 |
| Dodl | £15 | £38 | £75 | £150 | £375 |
| Barclays | £24 | £24 | £24 | £24 | £24 |
| AJ Bell | £45 | £62 | £62 | £62 | £62 |
| Interactive Investor | £88 | £88 | £88 | £88 | £180 |
| Fidelity | £120 | £120 | £120 | £120 | £120 |
| Hargreaves Lansdown | £63 | £115 | £178 | £178 | £178 |
At 4 trades a year, Barclays is the cheapest full-range platform at £24, because it has no account fee and you only pay £6 when you trade. If you trade twice a month (24 trades a year), Barclays rises to £144, and AJ Bell (£162 above £17,000) is about the same.
Most platforms charge less if you invest through a monthly regular investment rather than placing trades yourself. AJ Bell, HL, ii and Barclays all offer free regular investing.
FX fees: the hidden cost of US shares
Buying a US share means converting pounds to dollars, and platforms charge for it. This is often bigger than the dealing charge.
Cost of buying £1,000 of a US share, FX plus dealing:
| Platform | FX fee (first slice) | Dealing | Total |
|---|---|---|---|
| Trading 212 | 0.15% | £0 | £1.50 |
| Dodl | 0.75% | £0 | £7.50 |
| Freetrade (Basic) | 0.99% | £0 | £9.90 |
| Interactive Investor (Core) | 0.75% | £3.99 | £11.49 |
| AJ Bell | 0.75% | £5 | £12.50 |
| Fidelity | 0.75% | £7.50 | £15.00 |
| Barclays | 1% | £6 | £16.00 |
| Hargreaves Lansdown | 0.99% | £6.95 | £16.85 |
You pay FX again when you sell. Most full-service platforms reduce the rate on larger trades, typically to 0.25% on the part of a trade above £20,000 to £40,000. Freetrade’s paid plans cut its FX fee to 0.59% (Standard) or 0.39% (Plus). FX rates are as published by each platform or reported in 2026; check them before you trade.
If you mainly buy US shares, Trading 212 is far cheaper than anything else here.
Which share dealing ISA should you choose?
Mostly UK shares and sterling ETFs, any size: Trading 212 or Freetrade. Both are free with no dealing fees. Trading 212 also has a web platform; Freetrade is app-only.
US shares: Trading 212, for its 0.15% FX fee.
You want a full-service platform with research, bonds and gilts, and a wide range of investment trusts:
- Trading occasionally: Barclays (£6 a trade, no account fee)
- Trading monthly: AJ Bell (£42 a year cap in the ISA, £5 a trade)
- Portfolio over £100,000 and trading often: Interactive Investor’s flat fee
ETFs only: InvestEngine is free with no FX fee on its DIY service, but it doesn’t offer individual shares.
HL and Fidelity are the most expensive for shares at most sizes. Choose them for their research and service, not for cost. See HL fees explained.
Things to check before you choose
- Stamp duty: UK share purchases carry 0.5% stamp duty on every platform. It doesn’t apply to ETFs or US shares.
- Range: the zero-fee apps cover thousands of shares and ETFs but fewer bonds and less research. Dodl offers a shorter list of popular shares.
- Transferring later: moving US holdings out of Freetrade costs £17 per holding. See our ISA transfer guide.
- Flexible ISA: Trading 212, Freetrade and Barclays let you withdraw and replace money in the same tax year. AJ Bell, HL, Fidelity and ii don’t.
If you mainly hold funds rather than shares, see the cheapest stocks and shares ISA by portfolio size instead. Use the fee calculator to compare platforms at your exact portfolio size and trading frequency.