A Cash ISA (Individual Savings Account) lets you earn interest without paying tax on it. For the 2024/25 tax year, which runs from 6 April 2024 to 5 April 2025, you can save up to £20,000 across all your ISAs, tax-free.

You can save up to £20,000 each tax year across all your ISAs (not just with Tandem). The overall amount a customer can hold across their Cash ISAs is £250,000.

Yes. You can now subscribe to more than one ISA of the same type in the same tax year (since April 2024). Just make sure your combined contributions don’t go over the annual £20,000 limit.

No – all interest earned in your ISA is completely tax-free and doesn’t use up your allowance.

Yes, both our Instant Access and Fixed Rate Cash ISAs are flexible. That means you can withdraw and replace money in the same tax year without eating into your allowance. For example, if you deposit £20,000 but withdraw £5,000, you can still replace that £5,000 within the same tax year without exceeding your £20,000 limit.

Instant Access: withdraw and replace freely.

Fixed Rate: you can withdraw, but an early withdrawal penalty applies.

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Yes. You can transfer an ISA from another provider without it affecting your allowance. Just open a Tandem Cash ISA and start the transfer in the app.

Yes. Simply start the process with your new provider and they’ll contact us. Transfers normally process with 4-5 working days, but can sometimes take up to 15 working days. If you’re in a Fixed Rate ISA, an early withdrawal charge will apply.

Interest is calculated daily and paid monthly, tax-free.

Yes. You can hold up to 20 Tandem ISAs (Instant Access or Fixed Rate), so you can separate savings goals or take advantage of new rates.

You’ll have a 14-day window to decide whether to reinvest, move into an Instant Access ISA, withdraw, or transfer to another provider. If we don’t hear from you, your funds move into a Matured Funds Cash ISA at a variable rate so they keep earning interest tax-free

Yes. Tandem is a fully regulated UK bank. Your savings are protected up to £120,000 by the Financial Services Compensation Scheme (FSCS).

Part of your deposits help fund greener choices for others — like home energy upgrades, low emission vehicle, and solar panels. In 2024, Tandem customers helped save over 70,000 tonnes of CO₂, the equivalent of taking 15,000 petrol cars off the road for a year.

Instant Access Cash ISA – variable tax-free rate, dip into your savings anytime.

Fixed Rate Cash ISA – fixed rate, with funds locked in for a fixed term. Great for long-term saving with a guaranteed return.

Both are FSCS-protected up to £120,000.