Skip to content
Money GuideAll guides
How-to · Step-by-step

How to open a Cash ISA in the UK

In short. If you're 18 or over and a UK resident, you can open one or more Cash ISAs each tax year and pay in up to £20,000 across all your ISAs combined. Most providers let you open online in about 10 minutes.

A Cash ISA is a savings account where interest is tax-free. Since 6 April 2024 you can pay into more than one Cash ISA in the same tax year, as long as your total ISA contributions stay within the £20,000 annual allowance.

Last reviewed:

·Estimated time: 15 min·Cost: Free

What you'll need

  • National Insurance number
  • Proof of identity (passport or driving licence)
  • UK current account for funding

The steps

  1. 01

    Check you qualify

    You must be a UK resident aged 18 or over (16 for cash-only ISAs that opened before 6 April 2024 rules; from 6 April 2024 the minimum age is 18). Crown servants serving overseas also qualify.

    Official link →

  2. 02

    Compare account types

    Cash ISAs come in easy-access (variable rate), fixed-rate (locked for a term), notice and regular-saver variants. Check whether the account is 'flexible' — flexible Cash ISAs let you withdraw and replace money in the same tax year without using new allowance.

  3. 03

    Apply online or in branch

    Most banks and building societies offer Cash ISAs. Provide your name, address, date of birth and National Insurance number. The provider must verify your identity electronically or by document.

  4. 04

    Fund the ISA within the tax year

    Transfer money from a UK bank account by faster payment or standing order. Make sure any deposits are made by 5 April to count towards the current tax year's £20,000 allowance.

  5. 05

    Set up a transfer from any existing ISAs (optional)

    Don't withdraw — that would lose the tax wrapper. Instead, ask the new provider to arrange an ISA-to-ISA transfer; the original allowance is preserved.

    Official link →

Common pitfalls

  • Don't withdraw money to 'move' an ISA — always use a formal ISA transfer
  • Stay within £20,000 total across all ISA types (Cash + S&S + LISA + IF)
  • Fixed-rate ISAs usually charge an interest penalty for early access

FAQ

Can I open more than one Cash ISA in the same tax year?
Yes, since 6 April 2024. The combined deposits across all your ISAs still can't exceed the £20,000 annual allowance.
Is my Cash ISA protected?
Yes — eligible deposits with a UK-authorised bank or building society are covered by FSCS up to £85,000 per banking licence.
What if I pay in more than £20,000?
HMRC may treat the excess as outside the ISA wrapper. Contact the provider and HMRC as soon as you notice — they'll usually arrange a 'repair' of the over-subscription.
← All how-to guides