Compare Flexible ISAs

Choose the best flexible ISA to make the most of your tax free allowance this year.

Investment ISAs put your capital at risk & you may get back less than you originally invested

Stocks & Shares ISA

from Best Invest

ISA Option
Regular Savings
Allows ISA Transfers
  • Fund Choice: Over 2,500 funds, UK shares, investment trusts and ETFs or choose Ready Made & Managed Portfolios
  • Invest From: No minimum

Why we like it: Pick your own investments or choose a Ready-made Portfolio. Some of the lowest investment ISA account fees available. Tiered service fees of 0.2% or less a year, no set-up fees and share dealing for just £4.95 per trade. You don’t pay anything to open your ISA or buy funds, and share dealing costs just £4.95 per trade. Voted Best ISA Provider at the City of London Wealth Management Awards 2020. Capital at risk.

What is a flexible ISA?

A flexible ISA, or flexi-ISA, is a type of ISA that lets you re-use your ISA allowance when you make a withdrawal in the same tax year that you’ve made a contribution.

It provides an added layer of flexibility to Cash ISAs and Stocks and Shares ISAs.

In a non-flexible ISA, any withdrawals you make from your account after you’ve used your ISA allowance result in you losing that portion of your allowance permanently.

However, a flexible ISA allows you to add that money back in after withdrawing, even if you’ve used your full allowance for that tax year.

Here are some examples of using a flexi-ISA and a standard ISA to explain how they compare.

Non-flexible ISA example:

  • You contribute £20,000 to your ISA at the beginning of the tax year, using your entire ISA allowance
  • You make a withdrawal of £5,000 later in the tax year to fund an urgent payment
  • Later in the same tax year, you have £5,000 ready to put back into your ISA
  • But as it’s not a flexi-ISA, you can’t put it back in as you’ve already used your full £20,000 ISA allowance, leaving you with only £15,000 of ISA wrapped savings for the tax year

Flexible ISA example:

  • You contribute £20,000 to your ISA at the beginning of the tax year, using your entire ISA allowance
  • You make a withdrawal of £5,000 later in the tax year to fund an urgent payment
  • Later in the same tax year, you have £5,000 ready to put back into your ISA
  • As you have a flexi-ISA, you are allowed to add the £5,000 back in to get back to your total £20,000 of ISA savings for the tax year

With a flexi-ISA, you don’t have to worry about making ad hoc withdrawals from your ISA account throughout the tax year as you can add it back in if your circumstances change without it affecting your allowance.

How do I know if my ISA is flexible?

If you already have an ISA account, you can check with your ISA provider whether it is classed as a Flexible ISA.

How to check if your ISA is flexible:

  1. Look at your account opening documents or e-mails
  2. Look at your ISA provider’s website under the ISA account details or the FAQs section
  3. Give your ISA provider’s customer service team a call, or send them an e-mail

How much can I withdraw from a flexible ISA?

You can withdraw as much as you like from a flexible ISA. However, only your current tax year’s ISA subscriptions are flexible and so this aspect is capped at £20,000.

For example, if you withdrew £100,000 from your ISA account, you could only put up to £20,000 back in.

What are the different types of Flexible ISAs?

Flexible ISAs come in the form of Stocks and Shares ISAs and Cash ISAs – which one you choose to invest in depends on your personal investment preferences and circumstances.

Stocks and Shares ISAs invest in shares listed on the stock market or funds managed by investment professionals. Cash ISAs, on the other hand, invest only in Cash and return a rate of interest on your savings.

Stocks and Shares ISA investments can fall in value as well as rise, but the potential for returns is much higher.

Cash ISAs have typically low returns as interest rates are currently at record lows in the UK; however, your savings cannot go down in value so they are a lower risk option for many investors.

Who provides flexible ISAs?

There are many different flexible-ISA providers that offer a range of flexi-ISA products.

Many banks and building societies provide flexible Cash ISAs, while investment platforms and some banks provide flexible Stocks and Shares ISAs.

The biggest choice you need to make is between a Stocks and Shares flexi-ISA and a Cash flex-ISA.

Once you’ve decided this, you can compare providers for each one and make your selection.

Top tips for comparing flexible ISA providers:


  • Cash ISAs do not charge an ongoing fee, but Stocks and Shares ISAs have a platform charge
  • Check the annual management charge for each ISA provider
  • Check dealing fees, account closure fees and any other ad hoc charges that may apply


  • Many Stocks and Shares ISA providers offer exclusive research and investment tips
  • Review the quality of this research and think about whether it is worthwhile for your investment strategy
  • Think about how much of this content is only available to account holders and how much is free for everyone

Customer Service

  • ISA providers with higher fees may have better standards of customer service
  • This could be quicker response times, shorter telephone hold times, and customer service agents that have better training and more experience
  • Think about whether customer service is important for you – are you a new investor with a lot of questions, or will you be trading a lot and be likely to experience account issues?

Account Features

  • Some Stocks and Shares ISAs provide trading tools with their platforms
  • These can include share price notifications, stop losses and limit orders, and currency exchange services
  • Think about whether you need these features and if you’re willing to potentially pay more for them

What does it mean if an ISA is not flexible?

If your ISA account is not a flexible ISA, you cannot withdraw from your ISA without your money losing its ISA status.

For more information, read the flexible and non-flexible ISA examples at the top of this page.

What should I do if my ISA is not flexible?

If your ISA is not a flexible ISA there’s no need to panic. Non-ISAs are perfectly good investment accounts, but they just don’t give you as much flexibility over your allowance as flexi-ISAs do.

If you think you’ll be utilising your full ISA allowance most years but might need to dip in for withdrawals, then you can consider transferring your non flexi-ISA to a flexi-ISA.

Should I transfer my non flexi-ISA to a flexi-ISA?

If you want to get the benefits of a flexible ISA then you can transfer your existing ISAs to a flexi-ISA account.

How to transfer a non flexible ISA to a flexible ISA:

  1. Check with your current ISA provider if you’ll be charged for transferring out
  2. Obtain an ISA transfer form from your chosen flexible ISA provider
  3. Complete and return the transfer form to your new provider
  4. Your ISA provider will administrate your ISA transfer for you and notify you when complete

Note: Make sure you follow the above steps to transfer your ISA to a flexible ISA. If you withdraw your ISA and add it into a fresh ISA from your bank account you will be restricted to your annual ISA allowance of £20,000, which might not be enough to fit all of your ISA funds back in.

How do I open a flexible ISA?

Once you have decided on the best flexi-ISA for you, you can open an account in a matter of minutes via the following methods:

  1. Online
  2. Via a mobile App
  3. Over the phone
  4. Posting an application form and a cheque
  5. You can also contribute via monthly direct debit to your flexible ISA to build up your ISA savings gradually.

Flexible ISA application checklist:

  1. Have your National Insurance Number to hand
  2. Have your Debit Card details to make a lump-sum payment
  3. Have your bank details to hand if you want to contribute via Direct Debit
  4. You must be over the age of 18 for a Stocks and Shares ISA or 16 for a Cash ISA
  5. You must be a UK resident 

Frequently Asked Questions

Am I committed to one ISA provider forever?

No. You can switch providers with an ISA transfer if you wish. You can also contribute to other ISA providers in separate tax years.

Are ISA accounts safe?

ISA accounts are authorised and regulated by the Financial Conduct Authority (FCA). This means that all ISA providers are covered by the Financial Services Compensation Scheme (FSCS) for up to £85,000 if they go out of business.

Please note that this may not apply to the underlying holdings within a Stocks and Shares ISA, and will not cover standard investment losses. 

Can I lose money in an ISA?

You can lose money in a Stocks and Shares ISA if your investments go down in value. You cannot lose money with a Cash ISA.

Can I have a Joint ISA?

No, ISA stands for Individual Savings Account and must be solely owned for tax purposes.

Can I withdraw money from an ISA?

For Cash or Stocks and Shares ISAs, yes, although some Cash ISAs may charge a fee or void your interest if you surrender your policy before the fixed term has ended.

How do I withdraw money from my ISA?

Most providers will allow you to withdraw from your ISA online, via a mobile app, telephone, or by written instruction in the post.

How long does it take to withdraw from an ISA?

Most ISA withdrawals will complete in approximately five working days, but they could take longer depending on the assets you need to sell.

How much can I contribute to an ISA?

The annual ISA allowance is set by HMRC each year, and the current limit is £20,000 per person for the 2023/24 tax year.

When does the ISA tax year run to?

The annual ISA allowance runs in line with the normal tax year, which is 6th April to 5th April the following year. Your ISA allowance will refresh on 6th April each year.

Will I be charged for an ISA?

A Stocks and Shares ISA provider will charge an ongoing, annual platform fee as well as some ad hoc charges.

A Cash ISA could also charge if you withdraw money before the end of a fixed-term investment.