Advanced ISA Planner
Compare two ISA scenarios side by side over several tax years, each combining a Cash ISA and a Stocks and Shares ISA.
One-off payment of £14.99, no subscription
Not financial advice
What the planner does
You enter a lump sum, a monthly contribution, a time horizon, a risk profile and your age band. The planner shows each scenario's estimated final value, contributions and growth, the difference between the two, a year-by-year chart, and how much of the £20,000 ISA allowance each scenario would use over the whole period.
It does not recommend a split or tell you what to do with your money. The figures are illustrations of the inputs and preset assumptions you choose; they are not forecasts and not financial advice.
What the planner adds over the free ISA Calculator
Two scenarios side by side
Two scenarios (Stability and Growth) side by side, with the difference between them and a sentence saying where it comes from: with the presets both scenarios use the same rates, so the whole difference is the cash/investment split.
Free calculators: One estimate at a time.
Cash and Stocks and Shares ISAs together
A Cash ISA and a Stocks and Shares ISA combined in each scenario. The preset’s cash share, cash rate and investment return are shown as editable figures with their sources (the intermediate rate the FCA sets in COBS 13 Annex 2 as the standard maximum for regulated firms’ ISA projections, which is a projection convention, not a forecast or an FCA view of returns, and not an endorsement of this planner, and the Bank of England’s average quoted variable-rate cash ISA rate), dated 13 October 2026, with a reset to the preset.
Free calculators: One ISA type per tool.
Pound values for each scenario
Final value, contributed and growth in pounds for each scenario, with a low-to-high range and, if you tick it, values in today’s money at an inflation rate you set.
Free calculators: The Split Planner shows percentages only.
Allowance use over the whole horizon
Allowance use across the whole time horizon, this tax year’s remaining allowance from the payments left before 5 April and what you have already paid in, and what unused allowance could compound to.
Free calculators: Allowance bar for this tax year.
Chart and results table
Year-by-year chart of both scenarios with a shaded range band, a year-by-year table of contributions and balances, a CSV download and a print or save-as-PDF view.
Free calculators: Chart on the ISA Calculator only.
Age band and the cash ISA limit
Your age band (under 65 or 65 and over) applied to the cash ISA limit in every tax year of the estimate. Annual charges you enter are deducted from the investment return.
Free calculators: Cash ISA limit checked by the Cash ISA Calculator.
Worked example
What you get
- The Advanced ISA Planner, which opens in your web browser
- Access for as long as ISAPlan offers the planner, through a private link emailed to you after payment, with no account or sign-in
- A one-off payment of £14.99, with no subscription and no renewal charge
- Access for your own personal use: the private link is not to be shared or resold
Buy the Advanced ISA Planner
£14.99
One-off payment, no subscription. Sold by ISAPlan.
Access starts immediately, so on the payment page you will be asked to confirm that you want it to start at once and that you lose your 14-day right to cancel once it has.
The Advanced ISA Planner provides general information and illustrations only. It is not financial advice and does not guarantee any result.
Payment is taken by Stripe on its own secure page. Read the refund policy before you buy: access starts when we email your private link, which we do after your payment is confirmed, and you give up the 14-day right to cancel once it has started.
- Trading name
- ISAPlan
- Registered company
- Marble Cage Limited
- Registered in
- England and Wales
- Company number
- 17529115
- Registered office
- 82, Suite A James Carter Road, Mildenhall, IP28 7DE
- hello@isaplan.co.uk
Questions before you buy
How does access work?
There is no account and no password. After you pay, we email a private link to the address you gave at checkout. Opening the link opens the planner, and keeps it open for you on that device. Opening the link again on another device opens it there too.
What happens after I pay?
Checkout is handled by Stripe. After you pay you are taken to a thank-you page. Some payment methods take longer to confirm, and we email your private link and a written confirmation of your order to the address you gave at checkout only once payment is confirmed. Access starts when we send that email.
Is it a subscription?
No. It is a single payment of £14.99 for access for as long as ISAPlan offers the planner. Nothing renews, so there is no subscription to cancel. See the refund policy for the 14-day right to cancel.
What is the private link?
It is a web address, unique to your purchase, that opens the planner for you. Keep the email it came in: the link is how you open the planner again.
Can I share it?
No. The planner is for your own personal use. Anyone who has the private link can open the planner, so please keep it private and do not share or resell it.
What if the email does not arrive?
Check your spam or junk folder first. If it has not arrived within a few minutes, use the Contact page and choose "Billing / planner purchase", and we will try to help.
Can I get a refund?
Access starts when we email your private link, so refunds are not normally available once access has been granted, unless required by law. Before you pay you are asked to tick a box on the payment page to confirm that you want access to start immediately and that you lose your 14-day right to cancel once it has started. See the Refund & Cancellation Policy and use the Contact page if something went wrong with your payment or access.
Do the free calculators stay free?
Yes. The ISA Calculator, Cash ISA Calculator, Stocks and Shares ISA Calculator, Lifetime ISA Calculator and the planning tools need no account and no payment.
Does the planner give financial advice?
No. It is an educational calculator: it works out illustrative figures from the inputs and assumptions you choose. It does not assess your circumstances, recommend a product or a split, or suggest that you move money.