Regular saver vs Cash ISA: which is better?

How does a regular saver differ from a Cash ISA?

Both are deposit accounts. The differences that matter are how the money goes in, whether the interest is taxed, how much can be paid in and how easily it comes out. This page compares a regular saver held outside an ISA with a Cash ISA, using illustrative rates, and names no provider.

The numbers that matter

Overall ISA allowance, 2026/27

£20,000

Cash ISA limit from 6 April 2027

£20,000

Planned cut to £12,000 cancelled

Personal Savings Allowance

£1,000 / £500 / £0

Basic, higher and additional rate taxpayers, on interest outside an ISA

FSCS deposit protection

£120,000

Per person, per banking licence, ISA or not

How does a regular saver work?

A regular saver is usually an account where you pay in a set amount each month. Often it runs for a fixed period, often there is a monthly maximum, and often there are limits on withdrawals. Terms vary from account to account, so check the account’s own terms for the rate, the monthly limit, how long the saving period lasts and what happens if you withdraw.

This page treats a regular saver as an account held outside an ISA. If an account is held inside an ISA, the ISA rules apply to it instead.

How does a Cash ISA work?

gov.uk says you do not pay tax on interest on cash in an ISA. The overall ISA allowance for 2026/27 is £20,000 across all your ISAs, and a Cash ISA can use some or all of it. The Cash ISA limit stays the same after the Budget cancelled a planned cut. How easily you can take money out depends on the account’s own terms.

How much interest does each earn in a year?

The key arithmetic is timing. In a regular saver the money goes in month by month, so each payment earns the rate only for the months it has been in the account. With £250 paid in at the start of each month, the first payment earns for 12 months and the last for 1. Added up, that is 78 payment-months of interest, against 144 if the same £3,000 sits in the account from day one. At the same rate, a regular saver earns roughly half the interest over the first year.

An illustration. This is not a forecast and is not the rate on any account. It compares £3,000 paid in as £250 a month, at the start of each month, with £3,000 paid in on day one, at illustrative rates of 6% and 4% AER. AER is the annual equivalent rate. The sums assume interest compounds monthly, the rate stays the same all year and nothing is withdrawn.

At the same illustrative 6% AER, the regular saver earns £96.63, which is 54% of the £180.00 that the same rate earns on £3,000 held from day one. A lower illustrative 4% AER on £3,000 held from day one earns £120.00, more than the regular saver earns at 6%. Paid in month by month, 4% would earn £64.61.

Which column applies depends on the saver. Someone who has £3,000 now and pays it in on day one is in the right-hand column. Someone building the same total from income, £250 a month, is in the left-hand column, where the rate is the only difference.

When does tax on the interest matter?

Interest in a Cash ISA is tax-free. Interest outside an ISA, including from a regular saver, counts towards the Personal Savings Allowance: £1,000 for a basic rate taxpayer, £500 for a higher rate taxpayer and £0 for an additional rate taxpayer. Above it, interest is taxed at 20%, 40% or 45% in 2026/27.

The interest in the illustration is small. The largest figure, £180.00, is well inside both the £1,000 and £500 allowances, so a basic rate or higher rate taxpayer would pay no tax on it alone. An additional rate taxpayer has no allowance, so all interest outside an ISA is taxed, at 45% in 2026/27.

Tax starts to matter when other savings interest has already used up the allowance. The table adds the regular saver’s £96.63 to interest on other savings held outside an ISA, at an illustrative 4% AER, and shows the tax on the total at 2026/27 rates. It assumes the saver’s tax band is set by other income and that no Personal Allowance or starting rate for savings is left to cover the interest.

With £20,000 elsewhere, the interest on it is £800.00. Together with the regular saver’s £96.63 that is £896.63, inside the basic rate allowance but £396.63 over the higher rate allowance, which is taxed at 40%. A higher rate taxpayer’s allowance is already used up by the other savings, so the whole £96.63 from the regular saver is taxed, which adds £38.65 of tax.

With £30,000 elsewhere the total is £1,296.63: £296.63 is over the basic rate allowance and taxed at 20%, and £796.63 is over the higher rate allowance and taxed at 40%. The savings tax calculator works out the tax on your own interest and other income.

What about access and terms?

A regular saver usually asks for a set amount each month and often limits withdrawals. If an account has a monthly maximum, that maximum caps how much can go in and so how much interest the rate can earn. Terms vary, so check the account’s own terms for the rate, the monthly limit, the length of the saving period and what happens if you withdraw.

How easily you can take money out of a Cash ISA depends on the account. For reference, the highest easy access Cash ISA rate in our table is 4.86% AER (variable), checked 30 October 2026. That rate includes a bonus, so check how long it lasts and what the account pays afterwards. Rates change, so check our easy access Cash ISA table before comparing.

The FSCS protects eligible deposits up to £120,000 per person per banking licence, whether the account is an ISA or not. See ISA and FSCS protection.

Can you use both?

Yes. A regular saver held outside an ISA is not an ISA, so paying into it does not use the £20,000 ISA allowance, and its interest counts towards the Personal Savings Allowance. Interest in a Cash ISA is tax-free. To compare an ISA with a taxable account at rates you choose, use the ISA vs savings account calculator.

What changes from April 2027?

The Cash ISA limit stays £20,000, the same as the overall allowance, after a planned cut to £12,000 for savers aged 64 or under was cancelled in the Budget on 28 October 2026. Interest on savings held outside an ISA keeps counting towards the Personal Savings Allowance. See the Cash ISA limit.

The tax rates on savings interest outside an ISA also rise, to 24%, 44% and 49% by tax band. On the £30,000 case above, the same interest would be taxed £71.19 at basic rate, up from £59.33, and £350.52 at higher rate, up from £318.65. See savings tax 2027.