Short answer
Which is cheaper?
At £20,000, Vanguard models at £48/year versus interactive investor Core at £71.88/year. At £100,000, Vanguard models at £150/year versus ii Core at £71.88/year. Above £100,000 the model switches ii to Plus at £179.88/year, so compare exact portfolio size rather than assuming flat always wins.
- Small portfolios
- Vanguard usually wins while the flat ii fee is larger than 0.15%.
- Larger portfolios
- ii becomes compelling once fixed account pricing beats percentage drag.
- Range
- ii is broader; Vanguard is only like-for-like for Vanguard funds and ETFs.
Fee model
Platform, dealing and FX fees
| Fee area | interactive investor | Vanguard |
|---|---|---|
| Platform/account fee | Core £5.99/month up to £100,000 in the model; Plus £14.99/month above £100,000. | £4/month below £32,000; then 0.15% capped at £375/year. |
| Dealing fee | Core trades £3.99; Plus has lower fund trades and a modelled monthly trade credit. | £0; optional quote-and-deal ETF fees excluded. |
| FX fee | Core 0.75%; Plus 0.75% on first £50,000, then 0.25%; Premium 0.25%. | £0 |
| Investment range | Funds, shares, ETFs and investment trusts. | Vanguard funds and ETFs, no individual shares. |
| Flexible ISA | No | Yes |
Worked examples
Calculator-backed scenarios
- £20,000 fund ISA, no trades: Vanguard £48; interactive investor £71.88.
- £100,000 fund ISA, no trades: Vanguard £150; interactive investor £71.88.
- £100,000 fund ISA, £500/month FX: Vanguard £150; interactive investor Core £116.88.
- £150,000 mixed ISA, no trades: Vanguard £225 if holdings are Vanguard-compatible; interactive investor Plus £179.88.
These examples use the same fee assumptions as the main ISA fees calculator. They exclude fund ongoing charges, stamp duty, bid/offer spread, investment performance, and temporary promotions.
Important caveats
Before switching provider
Provider fees can change, and terms can vary by product, plan, transfer route, cash interest policy, and promotion. Verify the provider’s current terms before opening or transferring an ISA.
This page is factual educational content, not personal financial advice or a recommendation to buy, sell, transfer, or choose a specific investment platform.
FAQ
Common questions
Is interactive investor or Vanguard cheaper for a small ISA?
At £20,000, Vanguard models at £48/year versus interactive investor Core at £71.88/year in the calculator.
At what portfolio size does interactive investor become cheaper than Vanguard?
At £100,000, the model shows Vanguard at £150/year and interactive investor Core at £71.88/year, so ii is cheaper. The crossover depends on investment type and whether contributions are entered.
Does Vanguard ISA support individual shares?
Vanguard's ISA is limited to Vanguard funds and ETFs. interactive investor supports funds, shares, ETFs, and investment trusts.
Sources