Confirm whether you are tracking the current 2025/26 tax year or planning ahead for 2026/27. The tool resets the counter on 6 April and warns you of any current-year subscriptions that have not yet settled with the provider.

Add what you have already contributed this tax year to each ISA type: Stocks and Shares, Cash, Lifetime, Innovative Finance and Junior. Provide provider and amount. The tool aggregates and shows remaining allowance and a warning band as you approach £20,000.

If you have paid into two Cash ISAs or two Stocks and Shares ISAs, the tool checks the totals across all of them and confirms compliance with the post-April-2024 rules. It also flags the Lifetime ISA single-account-per-year rule.

A countdown to 5 April shows weeks and days remaining and the maximum amount you could still contribute. For pension contributors and higher-rate taxpayers, it suggests sequencing of pension carry-forward vs ISA topping-up.

If you want to move current-year money to a higher rate, the tool walks through the partial transfer mechanics: provider transfer form, 15-business-day timetable for cash and 30 days for stocks and shares, no allowance impact and no loss of tax wrapper.

For families, add Junior ISA contributions per child and see total annual family tax-free saving. The tool flags whether you are using both spouses' £20,000 allowances efficiently and whether bed-and-ISA from a general account would help shelter unwrapped gains before the next CGT allowance reset.

From 6 April 2024 HMRC simplified the ISA regime in three ways:

• Multiple subscriptions to the same ISA type in the same tax year are allowed (Lifetime ISA still one-per-year)
• Partial transfer of current-year contributions between providers is permitted
• The minimum age for adult Cash ISA is 18 across all types (previously 16 for Cash ISA only)

The annual £20,000 limit is unchanged. The reforms make rate-chasing and provider-switching practical for the first time without sacrificing allowance.

The Lifetime ISA pays a 25% government bonus on contributions, but withdrawals for any reason other than a qualifying first home (under £450,000), age 60+ or terminal illness incur a 25% withdrawal charge.

Critically, the 25% charge is on the larger inflated balance, so you lose more than the bonus you received. Contribute £1,000, get £250 bonus = £1,250. Withdraw early: 25% of £1,250 = £312.50, leaving £937.50 — a 6.25% net loss before any growth.

Cash ISA suits short-term goals (under 5 years) where capital preservation matters. Best rates as of 2025/26 cluster at 4.0 to 4.6%, often beating non-ISA easy access for higher-rate taxpayers.

Stocks and Shares ISA suits long-term wealth-building (5+ years) where short-term volatility is acceptable. Historic UK and global equity returns of 5 to 7% real per annum, but with 30 to 50% drawdown risk in any single year.

Many users hold both: cash for the next 6 to 24 months of life, stocks and shares for the rest.

Pre-April 2024 you had to transfer either the whole current-year contribution or none of it. Since April 2024, partial transfer of current-year and partial transfer of previous-year balances are both permitted across providers of the same type.

Practical strategy: leave a buffer of £1 to keep the original ISA open, transfer the bulk to the new better rate. Repeat as rate leaders change. Each transfer takes up to 15 business days for Cash ISA and up to 30 calendar days for Stocks and Shares.

If you hold investments outside an ISA, you can sell them, realise the gain (under the £3,000 2024/25 CGT allowance) and re-buy inside an ISA. This is called "Bed and ISA". The benefit: future growth and dividends are tax-free.

Watch the dealing costs and bid-offer spread, and ensure the gain on sale is within your annual CGT allowance to avoid triggering tax. For larger holdings, stage the sales over multiple tax years.