ISA Allowance Tracker

Why the April 5 ISA Deadline Matters

Every UK adult receives a fresh £20,000 ISA allowance at the start of each tax year (April 6). The catch: any unused portion of your current year's allowance disappears the moment April 5 passes. It does not roll over. It cannot be carried forward. It is simply gone.

This makes the final weeks before April 5 one of the most important windows in the UK savings calendar. If you have cash sitting in a regular current account or an easy-access savings account earning lower interest, moving even part of it into a Cash ISA before the deadline means that interest will be earned tax-free — permanently.

What Happens to Unused ISA Allowance?

Unlike pension contributions, ISA allowances have no carry-forward provision. HMRC does not let you "top up" a previous year's unused allowance in the next tax year. The £20,000 limit for 2025/26 is your ceiling from April 6, 2025 to April 5, 2026 — and then it resets to a new £20,000 for 2026/27.

Cash ISA vs Stocks & Shares ISA — Which Is Right Now?

Your £20,000 allowance can be split across different ISA types in a single tax year. The two most common choices are:

• Cash ISA — works like a savings account. Your money is protected by FSCS up to £85,000 per institution. Current best rates are around 4.9% AER for easy-access Cash ISAs. Ideal if you need the money within 1–3 years or want certainty.
• Stocks & Shares ISA — invests in equities, bonds, or funds. Higher long-term return potential but value can fall. Suitable for money you won't need for 5+ years. Not covered by FSCS (investment risk applies).

With Cash ISA rates at multi-year highs in 2026 (above 4.5% AER at leading providers), many savers who previously dismissed Cash ISAs as offering poor returns are revisiting them. At 4.9% AER, a fully-funded £20,000 Cash ISA earns approximately £980 in interest per year — completely tax-free.

The Personal Savings Allowance — Why ISAs Are More Valuable Now

Before April 2024, basic-rate taxpayers could earn £1,000 in interest per year tax-free outside of an ISA (the Personal Savings Allowance, or PSA). Higher-rate taxpayers received £500. Additional-rate taxpayers received nothing.

With savings rates now significantly higher than they were in 2021–22, many ordinary savers are finding their PSA is being consumed faster than expected. A basic-rate taxpayer with £25,000 in a standard savings account earning 4% AER would earn £1,000 in interest — exactly hitting their PSA limit. Any more savings, any higher rate, and they owe tax on the excess.

Inside a Cash ISA, all of that interest is permanently sheltered. The ISA allowance acts as a long-term tax shield — the more you move in over successive years, the larger the tax-free pot grows.

How to Open a Cash ISA Before April 5

Most UK banks and building societies allow Cash ISAs to be opened online within minutes. The key steps:

1. Compare rates — use our live rate comparison tool and filter to "Cash ISA" to see the current best rates from all major providers.
2. Check the terms — easy-access Cash ISAs let you withdraw without penalty. Fixed-rate Cash ISAs lock your money for 1–3 years at a higher rate. Choose based on whether you might need the money.
3. Open the account — most can be opened with just your National Insurance number and bank details. The process is typically 10–15 minutes online.
4. Transfer funds before April 5 — note that bank transfers can take 1–3 working days. If you are funding from a different bank, initiate the transfer by April 2 to be safe.