ISA Transfer Calculator

Bed and ISA means selling shares you hold in a general investment account (GIA) and immediately rebuying them inside a Stocks and Shares ISA. Once inside the ISA, all future gains and dividend income are sheltered from UK tax permanently.

The term “bed” comes from the old “bed and breakfast” strategy of selling and rebuying the same shares to crystallise a gain. The ISA version is still permitted because the rebuy happens inside a tax wrapper rather than in the same account.

When you sell shares outside an ISA, HMRC treats it as a disposal. If the shares have risen in value, you may owe Capital Gains Tax on the profit above your annual exemption (£3,000 in 2026/27). The key question is whether the future tax saving inside the ISA outweighs that upfront bill — which is exactly what this calculator answers.

If your gain falls within your remaining CGT exemption, the disposal is tax-free and the decision is straightforward: do it now.

If your gain exceeds your remaining CGT exemption — but not by too much — you can halve the upfront tax bill by splitting the transfer across two tax years:

1. Sell half your holding before 5 April, rebuy inside your ISA using this year's allowance.
2. After 6 April, sell the other half and use a fresh £3,000 CGT exemption for the new tax year.

This works best when the total gain is between £3,000 and £6,000 and you have your full annual exemption available. It does require two separate ISA contributions, so check you have sufficient ISA allowance (£20,000 per year).

Transfers between spouses and civil partners are exempt from CGT. This means you can transfer shares to your partner first — at no tax cost — and your partner can then carry out their own bed-and-ISA using their own CGT exemption and ISA allowance. Effectively this doubles the amount you can shelter tax-free in a single tax year.

There is an important distinction here: you cannot sell the shares into your partner's ISA. The transfer must be an outright gift, and once done, the shares are legally your partner's to deal with. They must decide to sell and rebuy inside their own ISA — you cannot instruct or require them to do so.