19 Days Until Your £20,000 ISA Allowance Expires: The Complete Last-Minute Checklist

A basic-rate taxpayer earns a £1,000 personal savings allowance before HMRC takes its cut. Higher-rate taxpayers get just £500. Additional-rate taxpayers get nothing.

So what happens when your savings grow beyond those thresholds? You hand 20% or 40% of every penny of interest to HMRC.

Here is the brutal arithmetic. £20,000 in a top easy-access savings account at roughly 4.5% earns £900 per year. A basic-rate taxpayer keeps all of it inside the personal savings allowance. But add that to existing savings interest and you cross the threshold fast. A higher-rate taxpayer with £15,000 already earning interest elsewhere is paying 40% tax on every pound of ISA-eligible interest they failed to shelter.

Inside a cash ISA paying 4.68% — the current top rate from Trading 212 — that same £20,000 earns £936 completely tax-free. Forever. Not just this year. Every year that money sits in the ISA wrapper, the interest compounds without HMRC touching it.

The gap widens every year. Over a decade, a higher-rate taxpayer sheltering £20,000 per year in a cash ISA keeps roughly £4,000 more than the taxable equivalent. That is not a rounding error. And if rates fall further — the BoE has already cut four times in twelve months — every pound sheltered at today's rate locks in a return that may not be available next year.

Monday–Tuesday: Check what you have already used. Log into every ISA provider you have paid into this tax year. Add up your contributions. The £20,000 annual limit covers all ISA types combined — cash, stocks and shares, innovative finance, and Lifetime ISA. If you have put £4,000 into a LISA, you have £16,000 left across the others.

Wednesday–Thursday: Decide your split. You can now hold multiple ISAs of the same type since the April 2024 rule change. But having a plan beats scattering money randomly. The right split depends on your tax bracket and goals:

• Higher-rate taxpayer with short-term goals? Max the cash ISA. At 4.68% tax-free, nothing else comes close for risk-free returns.
• Basic-rate taxpayer already using your personal savings allowance? Cash ISA for the next tranche of savings.
• Long time horizon and risk appetite? Stocks and shares ISA. The FTSE 100 yielding around 3.6% in dividends alone, plus growth potential, sheltered from capital gains tax.
• Under 40 and saving for a first home or retirement? Consider a Lifetime ISA — the 25% government bonus on up to £4,000 is free money. But act fast: the LISA is being scrapped, with new accounts closing by 2028.

Friday: Open the accounts. Do not wait. ISA providers get overwhelmed in the final week of March. Application backlogs, verification delays, and funding windows mean an account opened today is funded by next week. An account opened on 3 April might not be funded in time.

For our breakdown of how to divide your allowance across ISA types, see our ISA splitting guide.

Fund new accounts immediately after opening. Most easy-access cash ISAs accept instant bank transfers. Fixed-rate ISAs typically give you 14–28 days to fund after opening — check your provider's window. If it closes after 5 April, your contribution counts against next year's allowance or may be rejected entirely.

Transfer old ISAs to better rates. This is the move most people miss. If you have cash ISAs from previous years paying 1% or 2%, transferring them to a provider paying 4%+ is worth hundreds of pounds per year — and it does not use any of your current year's allowance.

Top transfer rates right now:

• Moneybox: 4.26% easy access (best for transfers in)
• Cynergy Bank: 4.05% easy access (no bonus gimmicks, straightforward)
• Coventry Building Society: 4.21% one-year fix

Critical rule: always use the official ISA transfer process. If you withdraw money from an old ISA and redeposit it into a new one, it counts as a new contribution against your £20,000 limit. The transfer process preserves your previous years' tax-free status. Every provider has a transfer form — use it.

Transfers between cash ISAs take up to 15 working days. Transfers from stocks and shares ISAs take up to 30 calendar days. If you are transferring, initiate it this week — not next.

31 March – 2 April: The last comfortable window. Bank transfers typically clear same day or next business day. If you are funding a cash ISA with a simple bank transfer, you have until about 2 April to be safe with standard payment processing.

3–4 April: Danger zone. Provider systems strain under deadline traffic. Some platforms restrict new account openings in the final 48 hours. Others accept applications but cannot process funding in time. Do not discover this on 4 April at 11pm.

5 April: Absolute deadline. Contributions must be received — not sent, received — by the end of 5 April. For most providers, this means the money must be in the ISA account, not in transit. Check your provider's specific cut-off time — MoneyHelper has guidance on ISA deadlines and provider processes. Some close at 11:59pm, others at 3pm for manual processing.

A checklist for the final 48 hours:

• Verify every ISA contribution has landed (check statements, not just pending transactions)
• Confirm any in-progress transfers have completed — chase your provider if they have not
• If you have unused allowance and cash available, make a final top-up even if it is only £500 or £1,000
• Screenshot your ISA balances and contribution confirmations for your records

Bed and ISA your taxable investments. If you hold shares or funds in a general investment account, sell them and rebuy inside a stocks and shares ISA. You crystallise any capital gain (covered by your £3,000 annual exempt amount for 2025/26), then future growth and dividends are permanently tax-free. This is especially powerful for dividend-paying stocks — the dividend allowance is just £500 for 2025/26.

Use your spouse's allowance too. A couple has £40,000 of combined ISA allowance. If one partner has savings sitting in a taxable account while the other has unused ISA space, gift the money across and shelter it. There is no tax on gifts between spouses.

Do not ignore the Lifetime ISA. Yes, it is being wound down. But if you already have one, or you are under 40 and can still open one, the 25% bonus on £4,000 means £1,000 of free money from the government — paid within weeks. That is an instant 25% return with zero risk. The £4,000 LISA limit sits within your overall £20,000 allowance.

Consider your children. Junior ISAs have a separate £9,000 allowance for 2025/26. If you have children under 18, this is another £9,000 of tax-free growth that resets on 6 April. For more on our comprehensive ISA guide, including Junior ISAs and all wrapper types.

The BoE has cut rates four times since February 2025 — from 4.75% down to 3.75%. Markets expect further cuts in 2026. That means today's cash ISA rates of 4.68% easy access are likely the best you will see for a while. Lock in a five-year fix at 4.32% (Tandem Bank) and you are earning above what the BoE pays for the next half-decade.

The Iran conflict is adding fresh uncertainty to the economic outlook. Oil prices are climbing, energy bills are under pressure again, and the BoE faces a harder choice between cutting rates to support growth and holding firm against inflationary risks. In that environment, locking in a guaranteed 4%+ return inside a tax-free wrapper is as close to a financial no-brainer as the UK offers right now.

For more on how savings rates are shifting, see our savings hub and the analysis of the 4-account strategy for falling rates.

This article is for informational purposes only and does not constitute financial advice. You should seek independent financial advice before making any investment decisions.