Cash ISA

Harpenden Building Society Cash ISA Review

An instant access cash ISA from Harpenden Building Society. It ranks 102nd of 115 instant access cash ISAs we track.

Variable rate

1.35%AER

Rate checked Oct 2026Got this account? Leave a review

Protection

FSCS£120,000

Min balance

£1

Max balance

No limit

Access

Instant

Interest paid

Annually

Transfers in

Accepted

How It Stacks Up

Ranks 102nd of 115

Instant access cash ISAs we track

Well below average
This account 1.35%
UK CPI (Aug 2026)
3.10%
Pays 1.75% less
Average instant access cash ISA
2.91%
Pays 1.56% less
Best instant access cash ISA
4.87%
Pays 3.52% less

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

A better-paying alternative

Trading 212 bank logo

Trading 212

Cash ISA

4.75%

AER

  • Pays 3.40% more than this Harpenden Building Society account
  • Includes a 1.15% bonus for 12 months, then 3.60%
Compare Cash ISAs

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A Good Fit For

  • Pro: New and existing savers
  • Pro: Savers who want instant access

Worth Weighing Up

  • Con: The rate is variable, so it can go down

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Estimated returns with Harpenden Building Society's Cash ISA

What you could earn with Harpenden Building Society's Cash ISA.

Estimated interest

£1,000 saved

£13.50

At 1.35% AER

£5,000 saved

£67.50

At 1.35% AER

£10,000 saved

£135

At 1.35% AER

£50,000 saved

£675

At 1.35% AER

Estimated over one year, 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 Harpenden Building Society Cash ISA

Jonny PeaseCo-Founder, DepositScout

Harpenden Building Society's Cash ISA pays just 1.35%, which is below the market average for cash ISAs and 3.90% behind the current category leader at 5.25%. At that rate you are also losing ground to inflation in real terms, sitting 1.75% below CPI of 3.1% as of Aug 2026. The account does open from £1 and accepts transfers in, which is handy, but I would look at alternatives first - Monzo's Select Access Cash ISA is paying 3.15% with the same instant access flexibility.

Compare Cash ISAs

2 alternatives to Harpenden Building Society's Cash ISA

Same type of account, closest on rate.

Common questions about the Cash ISA

D

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