Does an ISA Count Toward Personal Savings Allowance?

No. ISA interest does not count toward your Personal Savings Allowance (PSA). The PSA only applies to non-ISA savings interest — bank accounts, savings accounts, regular savers and similar held outside an ISA wrapper. So if you hold a cash ISA and a separate taxable savings account, the ISA interest is tax-free under ISA rules (separate from PSA), and only the taxable account’s interest uses your PSA. This makes ISAs structurally separate from the PSA framework.

This is the relationship between the two, for the 2026/27 tax year.

The two systems explained

The UK has two parallel tax-free savings frameworks:

Personal Savings Allowance (PSA)

The PSA allows you to earn some interest on non-ISA savings before paying tax.

• Basic-rate taxpayers: £1,000 PSA per tax year.
• Higher-rate taxpayers (40%): £500 PSA per tax year.
• Additional-rate taxpayers (45%): £0 PSA.

Interest above the PSA is taxed at your marginal rate (typically via your tax code or Self Assessment).

ISAs

ISAs have their own framework. All interest, dividends and gains inside an ISA are tax-free, regardless of how much you earn elsewhere. This is independent of the PSA.

Why the distinction matters

The two systems don’t interact. Consider three scenarios:

Scenario 1: All cash in a regular savings account

You’re a basic-rate taxpayer with £40,000 in a regular savings account at 4.5%:

• Annual interest: £1,800.
• PSA: £1,000 free.
• Taxable interest: £800.
• Tax at 20%: £160.

Net: £1,640 interest after tax.

Scenario 2: All cash in a cash ISA

Same £40,000 at the same 4.5%, but inside a cash ISA:

• Annual interest: £1,800.
• ISA tax-free: yes.
• Tax: £0.

Net: £1,800 interest after tax.

The cash ISA delivers £160 more in this case.

Scenario 3: Split — half in ISA, half outside

£20,000 in cash ISA at 4.5% = £900 interest, tax-free. £20,000 in regular savings at 4.5% = £900 interest, all within £1,000 PSA, tax-free.

Total: £1,800 interest, all tax-free. Same effective outcome as Scenario 2 because the PSA covers the non-ISA interest.

This is why for basic-rate taxpayers with modest savings, the ISA wrapper sometimes isn’t worth the admin — the PSA covers them anyway. The ISA becomes more valuable as:

• Your savings balance grows beyond PSA-coverable levels.
• Your tax band rises (PSA shrinks to £500 then £0).

When does the PSA stop being enough?

The break-even balance — where you fill the PSA and need the ISA wrapper to avoid tax — depends on your tax band and the interest rate.

At 4.5% interest:

• Basic rate (£1,000 PSA): PSA fills at £22,222 balance. Above this, marginal cash should arguably go in an ISA.
• Higher rate (£500 PSA): PSA fills at £11,111 balance. ISA worth more.
• Additional rate (£0 PSA): Every pound of interest is taxable. ISA always more attractive for new cash.

At 5.0% interest:

• Basic rate: £20,000 balance fills PSA.
• Higher rate: £10,000 balance fills PSA.
• Additional rate: £0.

These break-evens are useful rules of thumb. They tell you when to start prioritising the ISA wrapper.

What if I have multiple accounts and ISAs?

All non-ISA interest across all accounts (savings, current account interest, bond interest, dividends — wait, dividends use a different allowance) counts against the PSA.

The mechanics:

• Bank A: £200 interest.
• Bank B: £400 interest.
• Bank C savings ISA: £300 interest (ISA — doesn’t count toward PSA).
• Bank D regular saver: £150 interest.

Total non-ISA interest: £200 + £400 + £150 = £750. Within £1,000 PSA. No tax on any.

ISA interest of £300 is separately tax-free.

The PSA is per-individual, not per-account. So if you hold many small accounts, you sum them all up to compare against the PSA.

What counts as “savings interest” for the PSA?

The PSA applies to:

• Interest on savings accounts.
• Interest on bank current accounts (often small but counted).
• Interest on regular saver accounts.
• Interest on fixed-rate bonds.
• Interest on credit-union accounts.
• Income from certain National Savings & Investments products (some are tax-free without PSA needed, like Premium Bonds prizes; some count, like Income Bonds).
• Interest from peer-to-peer lending (outside an IFISA).

What doesn’t use the PSA:

• ISA interest (own tax-free framework).
• Dividends (use the separate Dividend Allowance).
• Premium Bonds prizes (tax-free under their own rules, don’t use PSA).
• Foreign-source interest paid abroad (treated under foreign income rules, not PSA directly).

For the full HMRC position, see gov.uk: Personal Savings Allowance.

Dividend Allowance — a separate £500 allowance

Confusingly, there’s also a £500 Dividend Allowance (2026/27 figure, reduced from £2,000 just a few years ago). This applies to dividends received outside an ISA, separately from the PSA.

So if you hold:

• £15,000 in non-ISA dividend-paying shares: £400 dividend income → covered by Dividend Allowance.
• £20,000 in non-ISA bonds: £900 interest → counts against PSA.
• £15,000 in cash ISA: £675 interest → tax-free under ISA, doesn’t use either allowance.

Three different tax-free frameworks working in parallel.

A practical rule of thumb

The ISA prioritisation guide for most savers:

1. Always fill the LISA first if you’re eligible and using it for first-home or retirement (25% bonus is unmatched).
2. Fill the cash ISA if you have more cash savings than your PSA can cover (typically £15,000–£25,000+ depending on tax band and interest rate).
3. Fill the stocks & shares ISA for long-term investments (CGT and dividend allowances are much smaller than PSA, so equity returns benefit more from ISA wrapping).
4. Beyond the ISA: cash above PSA needs careful tax handling; long-term investments outside ISA face CGT.

Worked example: deciding where to put new savings

Aisha is a higher-rate taxpayer with:

• £50,000 in regular savings at 4.5%.
• £20,000 in a stocks & shares ISA.

She has £10,000 of new savings to deploy.

Current taxable interest: £50,000 × 4.5% = £2,250.

• PSA at higher rate: £500.
• Taxable: £1,750.
• Tax at 40%: £700.

If she adds £10,000 to her existing savings:

• New balance: £60,000 → £2,700 interest.
• Tax: £880.
• Net: £1,820 interest.

If she puts £10,000 into her cash ISA instead:

• ISA balance grows; £10,000 × 4.5% = £450 interest, tax-free.
• Non-ISA savings remain £50,000 → £2,250 interest minus £700 tax = £1,550.
• Total interest: £450 + £1,550 = £2,000 — net of tax.

Difference: ISA delivers £180 more in year 1. Compounded over years, the ISA route becomes increasingly beneficial.

Internal links

• Do I pay tax on ISA withdrawals?
• Do I pay tax on savings interest UK?
• How does the personal savings allowance work?

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This guide is information, not regulated financial advice. Tax bands and allowances can change between budgets — confirm current figures on gov.uk before relying on specific numbers.