Easy access cash ISAsUp to 5.71%
Flexible ISAs: What they are and how they work
Before opening an ISA, it’s worth checking whether it’s flexible to make sure it’s the right account for you.
An ISA is a tax-efficient way to save money. Each tax year, you're given an annual ISA allowance (or a limit to the amount you can pay into an ISA). For the 2024/2025 tax year, this stands at £20,000.
Is my money safe?
The Financial Services Compensation Scheme (FSCS) guarantees that it will step in to compensate the first £85,000 (£170,000 for a joint account) you have saved with a UK-authorised bank, building society or credit union in the event that the business goes bust.
Best flexible cash ISA rates
Table: sorted by interest rate, promoted deals first
Compare other products
We currently don't have that product, but here are others to consider:
How we picked these
What is a flexible ISA?
A flexible ISA is an ISA that lets you withdraw funds and pay them back into your ISA account in the same tax year, without affecting your annual ISA allowance. This can apply to cash ISAs, stocks and shares ISAs and innovative finance ISAs, but not all providers offer flexible ISAs so you’ll need to check.
A flexible ISA means you won’t be penalised if you access some of your ISA funds.
How does a flexible ISA work?
Let’s say you’ve paid £20,000 into a flexible cash ISA, using your full ISA allowance for that year. In the same tax year, you decide to withdraw £10,000. Because the ISA is flexible, the withdrawal doesn’t affect your annual allowance and you can repay the £10,000 before the end of the tax year.
Note that you must repay it into the same ISA account you took it out of, although you can withdraw from a flexible cash ISA and replace it in a flexible stocks and shares or innovative finance ISA instead.
By contrast, if the ISA was not flexible and you’d paid in £20,000 but withdrawn £10,000, you wouldn’t be able to repay the £10,000 as this would mean you’d have exceeded your annual allowance.
Do I need a flexible ISA?
Ultimately, whether you need a flexible ISA is up to you. But if you think you could get close to using up your £20,000 annual ISA allowance and you plan to make withdrawals, it’s well worth choosing a flexible ISA.
On the other hand, if you know you won’t get close to reaching your annual ISA limit or you don’t plan to make any withdrawals, choosing a flexible ISA won’t be so important.
Pros and cons of flexible ISAs
Pros
- Enables you to withdraw funds and replace them within the same tax year without impacting your annual ISA allowance
- You can also withdraw funds from a cash ISA and replace them in a flexible stocks and shares or innovative finance ISA
- Good option if you need to access funds in an emergency
Cons
- Not all ISAs are flexible
- Flexible ISAs might not necessarily offer the best rates
- You must repay the funds into the same ISA account (unless you choose a different type of ISA)
Bottom line
Choosing a flexible ISA could be a great option if you’re worried that you will get close to using your full ISA allowance and might need to make some withdrawals. Just remember that not all providers offer flexible ISAs and it’s important to check how competitive the account is before making a decision.
Frequently asked questions
We show offers we can track - that's not every product on the market...yet. Unless we've said otherwise, products are in no particular order. The terms "best", "top", "cheap" (and variations of these) aren't ratings, though we always explain what's great about a product when we highlight it. This is subject to our terms of use. When you make major financial decisions, consider getting independent financial advice. Always consider your own circumstances when you compare products so you get what's right for you. Most of the data in Finder's comparison tables has the source: Moneyfacts Group PLC. In other cases, Finder has sourced data directly from providers.
More resources on Finder
More guides on Finder
-
Working from home statistics: How many people work from home?
Our research found that 41% of Brits work from home at least some of the time as of March 2025. We look at who is working from home and how working from home affects productivity.
-
Compare savings accounts with compound interest
We look at the definition of compound interest, what it concretely means and how you can use it to grow your savings more quickly.
-
Offshore savings accounts
Learn how offshore savings accounts work, which taxes you need to pay and how to score the best deal.
-
Halifax savings rates review, from savings accounts to ISAs
Whatever you’re saving for, find the right Halifax savings account for you. Our detailed guide walks you through which of Halifax’s savings accounts is for you.
-
Tesco Bank savings rates
Learn about the savings options at Tesco Bank, from ISAs to fixed rate savings. We highlight Tesco Bank savings accounts’ features and pros and cons.
-
Santander savings accounts
Our guide to Santander’s savings accounts. From ISAs to regular savings, from fixed-term to junior saving accounts, Santander might have the option for you.
-
Yorkshire Building Society savings accounts and interest rates
Yorkshire Building Society offers a range of savings accounts. If you’re looking to save, see our guide for more.
-
Nationwide savings account rates compared
Nationwide’s savings account options explained. Whether you’re happy to tie up your money or need instant access, we’ve covered the options.
-
Best Post Office savings account rates evaluated
Read about the Post Office and the savings accounts they offer. Find out more about the services Post Office Money provide, and see if they are right for you.
-
Barclays savings rates
Whatever you’re saving for, big or small, Barclays Bank offers a full range of savings accounts. Our guide takes you through the full range.