Independent product · Financial tools
CompareStockISA
A financial comparison product that explains costs without pretending a single platform is right for everyone.
Visit projectProblem
Different platform, dealing and FX structures made cost comparison unreliable and easy to oversimplify.Solution
One set of questions and one consistent calculation method applied to every supported provider.Impact
Clear annual cost breakdowns, backed by 377 automated tests covering provider rules and unusual cases.One investor profile
- Portfolio
- £50,000
- Trades / year
- 24
- International
- 20%
Every fee rule
- Platform
- Dealing
- FX
- Caps
- Tiers
- Allowances
The same behaviour and assumptions are used for every provider.
A comparable annual cost
- 1Platform A£84
- 2Platform B£120
- 3Platform C£186
The problem
UK investment platforms combine custody fees, dealing charges, foreign-exchange costs, caps, thresholds, free-trade allowances and minimum-activity rules. A headline percentage rarely tells someone what they will pay.
The solution
CompareStockISA asks about investment size, annual trades, shares versus funds and UK versus international exposure. It applies that same behaviour to every provider, then shows the estimated annual cost and where the money goes.
The same maths for every provider
Provider rules are stored separately from the interface, so a pricing change does not require rewriting the calculator. Costs are applied in a fixed order, using whole trades and consistent treatment of dealing, foreign exchange and activity discounts.
The evidence
The calculator handles flat charges, percentages, caps, tiers, thresholds, free trades and market-specific FX. Unsupported combinations are explained instead of forced through the wrong formula. There are 377 automated tests covering provider rules and awkward edge cases.
The calculator compares costs; the investor still decides
The product does not recommend a provider. It compares estimated costs using published fees and shows its assumptions, leaving the investor to weigh service, features and risk.
The impact
CompareStockISA turns a fragmented research task into a consistent, inspectable calculation and gives every provider the same mathematical treatment.
The result