How the ISA Allowance Works

What is the ISA allowance?

The ISA allowance is the maximum amount you can contribute to ISAs in a single tax year. It applies across all ISA types combined.

You do not get a separate allowance for each ISA.

How the allowance is shared

You can split your allowance across:

• Cash ISAs

• Stocks & Shares ISAs

• Lifetime ISAs

For example:

• Part into a Cash ISA

• Part into a Stocks & Shares ISA

• Up to £4,000 into a Lifetime ISA (counts toward the total)

👉 Track this visually with the ISA Allowance Optimiser.

What happens if you exceed the allowance?

If you contribute more than the allowance:

• HMRC may remove the excess

• Tax benefits on the excess can be lost

• You may be asked to correct the position

This often happens unintentionally when using multiple providers.

Does withdrawing money reset the allowance?

No. With most ISAs:

• Withdrawals do not restore allowance

• Once used, that year’s allowance is gone

(Some providers offer flexible ISAs with different rules.)

Key takeaway

The ISA allowance is generous but easy to mismanage when using multiple ISAs. Tracking contributions helps avoid accidental breaches and keeps your savings fully tax-efficient.