What interest rate does the Castle Trust Bank 5 year Fixed Rate e-Cash ISA pay?

The Castle Trust Bank 5 year Fixed Rate e-Cash ISA pays 4.81% AER fixed.

How much interest could I earn?

Saving £10,000 for 5 years would earn about £2,648 at 4.81% AER. This assumes the rate stays the same and interest stays in the account.

How much can I pay in?

You can deposit at least £1,000 and up to £500,000.

Can I withdraw my money?

No. Withdrawals aren't allowed until the account matures.

When is interest paid?

Interest is paid at the end of the term.

Who can open this account?

New and existing Castle Trust Bank customers can open it. You can open it online or in the app.

Is my money protected?

Yes. Eligible deposits are protected by the Financial Services Compensation Scheme (FSCS) up to £120,000 per person, per banking licence.

Can I transfer an existing ISA in?

Yes, transfers in from other ISAs are accepted.

How does it compare with other five-year cash ISAs?

At 4.81% AER it ranks 9th of 26 five-year cash ISAs we track. The best pays 5.12% and the average is 4.61%.

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Cash ISA

Castle Trust Bank 5 year Fixed Rate e-Cash ISA Review

A competitive five-year cash ISA from Castle Trust Bank, with a £1,000 minimum deposit. It ranks 9th of 26 five-year cash ISAs we track.

Rate checked Oct 2026Got this account? Leave a review

Fixed rate · 5 years

4.81%AER

Rate checked Oct 2026Got this account? Leave a review

Protection

FSCS£120,000

Min balance

£1,000

Max balance

£500,000

Access

At maturity only

Interest paid

On Maturity

Transfers in

Accepted

How It Stacks Up

Ranks 9th of 26

5-year cash ISAs we track

Above average

This account 4.81%

UK CPI (Aug 2026): 3.10%; Pays 1.71% more
Average 5-year cash ISA: 4.61%; Pays 0.20% more
Best 5-year cash ISA: 5.12%; Pays 0.31% less

Inflation: ONS. Averages and best rates: accounts on DepositScout.

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A Good Fit For

Pro: New and existing savers

Worth Weighing Up

Con: Your money is locked in for 5 years
Con: You need at least £1,000 to open it
Con: Not flexible: money you withdraw can't be replaced without using more allowance

Good to Know

You are permitted to withdraw the full amount (including transferring to another ISA provider) but this is subject to a loss of interest.

Please verify all details with the provider – see our Disclaimer

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Estimated returns with Castle Trust Bank's Cash ISA

What you could earn with Castle Trust Bank's 5 year Fixed Rate e-Cash ISA.

Estimated interest

£1,000 saved

£265

At 4.81% AER

£5,000 saved

£1,324

At 4.81% AER

£10,000 saved

£2,648

At 4.81% AER

£500,000 saved

£132,388

At 4.81% AER

Estimated over the 60-month term, if the rate stays the same and interest is left in. Amounts outside the account's minimum or maximum aren't shown.

Our Expert Opinion on Castle Trust Bank 5 year Fixed Rate e-Cash ISA

Jan WatermannCo-Founder, DepositScout

Castle Trust Bank's five-year Fixed Rate e-Cash ISA pays 4.81%, which sits above the cash ISA market average but 0.31% behind the category leader at 5.12%. At 1.71% above August 2026 CPI of 3.1%, it does at least beat inflation in real terms. The minimum is £1,000 and transfers in are accepted, so it suits savers with existing ISA pots who want a long, inflation-beating fix. The genuine catch is total illiquidity: no access until maturity, with charges if you withdraw early.

Compare Cash ISAs