The end of the tax year has a habit of arriving faster than expected. One moment it is January, and the next you are in late March, realising you have left thousands of pounds of allowances untouched. With the ISA deadline 2026 falling on 5 April, the window to act is shorter than most people think.
The deadline for ISA contributions is the same date every year, yet it catches people out time and again. The same goes for pension top-ups, dividend decisions, and a handful of other allowances that expire the moment the tax year closes. None of these roll over. ISA year end is not a soft suggestion. It is a hard cut-off, and anything left unused is gone for good.
This is not a list of obscure tax planning tricks. These are mainstream allowances that exist specifically for people like you to use. HMRC will not remind you. Your bank almost certainly will not either. So here is what to work through before 5 April 2026.
Gather this information first
Before you do anything else, pull together the following. You will need it to work through every item on this list accurately, and having it ready saves you from either missing an allowance or accidentally overcontributing somewhere.
- Your total income for the 2025/26 tax year, covering employment, self-employment, rental income, dividends, and interest. Every source counts
- How much you have already contributed to any ISA this tax year and which providers you have used
- Your current pension pot value and any contributions made since 6 April 2025, including employer contributions
- Any capital gains you have already realised this year from selling investments, property, or other assets
- Your National Insurance record, which you can check directly on GOV UK
Ten minutes spent pulling this together will make the rest of this process straightforward.
Use your £20,000 ISA allowance
The annual ISA allowance is £20,000 per adult. It does not roll over. If you do not use it by 5 April, it is gone permanently, and you cannot carry it into the following tax year.
How the allowance works
You can split the £20,000 across different ISA types in the same tax year. The main types available are:
- Cash ISA: Straightforward savings with interest sheltered from income tax
- Stocks and Shares ISA: Investments in funds, shares, and bonds with gains and income protected from tax.
- Innovative Finance ISA: Peer-to-peer lending wrapped in an ISA.
- Lifetime ISA: For first-time buyers or retirement saving, with its own sub-limit detailed below.
The total across all ISA types cannot exceed £20,000 in a single tax year. Contributions to a Lifetime ISA count toward this overall limit.
Who this applies to
Any UK resident aged 18 or over can open and contribute to most ISA types. Cash ISAs are available from age 16. Critically, if you have a spouse or civil partner, they each hold their own separate £20,000 allowance, meaning up to £40,000 between you could be sheltered from tax before 5 April.
If you have cash sitting in a standard savings account, moving some or all of it into an ISA means future interest is completely free of income tax and does not erode your Personal Savings Allowance.
The Lifetime ISA: a £4,000 sub-limit worth knowing
If you are between 18 and 39, you can open a Lifetime ISA and contribute up to £4,000 per tax year. The government adds a 25% bonus on contributions, meaning up to £1,000 of free money added to your account annually. That £4,000 counts toward your overall £20,000 ISA allowance.
What the Lifetime ISA can be used for
The Lifetime ISA is designed for two specific purposes:
- Buying your first home, where the property must be priced at £450,000 or under
- Retirement from age 60, when funds can be withdrawn without penalty
Withdrawing money for any other reason triggers a 25% government withdrawal charge, which effectively claws back more than just the bonus. This is not a flexible savings product, but for those it suits, the 25% annual bonus is genuinely difficult to match elsewhere.
Who this applies to
You must be under 40 to open a Lifetime ISA, though you can continue contributing until age 50. If you are a first-time buyer saving toward a deposit, or you want a tax-sheltered retirement pot alongside a workplace pension, this is worth using before 5 April if you have not already contributed this year.
Top up your pension before 5 April
Pension contributions attract income tax relief at your marginal rate. A basic rate taxpayer contributing £800 sees £1,000 land in their pension once basic rate relief is applied. Higher and additional rate taxpayers can reclaim further relief through their Self Assessment tax return. The result is that pension contributions remain one of the most tax-efficient ways to save in the UK.
Understanding the annual allowance
The pension annual allowance for 2025/26 is £60,000, or 100% of your UK earnings if that is lower. This covers all contributions into your pension, including those made by your employer. Most people are comfortably below this limit, but it is worth confirming if you have had a high-income year or received substantial employer contributions.
For those with income above £260,000, the tapered annual allowance may reduce this limit, so it is worth taking advice if you are in that position.
Carry forward: using previous years’ unused allowance
If you have not used your full annual allowance in any of the previous three tax years, you may be able to carry that unused allowance forward and contribute more than £60,000 this year. Carry forward works in order, starting with the oldest year first.
This is particularly useful if you have recently had a strong financial year, sold a business, or are approaching retirement and want to accelerate pension saving. Your pension provider may be able to confirm your carry-forward position, though a qualified accountant can work through it more precisely.
Who this applies to
Employees, self-employed individuals, company directors, and anyone with UK earnings can contribute to a pension and receive tax relief. Directors paying themselves through a limited company should also consider employer pension contributions, which are a deductible business expense and do not attract National Insurance. This is covered in more depth in our guide to maximising profits and minimising tax for limited companies.
The £3,000 CGT annual exempt amount
Capital Gains Tax is charged on profits from selling or disposing of assets above a set threshold. For 2025/26, each individual has an annual exempt amount of £3,000. Gains up to this figure are free of CGT. Anything above it is taxed at:
- 18% for basic rate taxpayers on most assets
- 24% for higher and additional rate taxpayers on most assets
- 24% on residential property gains for higher rate taxpayers
Using the exempt amount before 5 April
If you hold investments sitting on an unrealised gain, you may want to consider realising some of that gain before 5 April to use this year’s exempt amount. This is a common strategy with investment portfolios and should not be driven purely by tax considerations, but it is worth factoring into your year-end review.
If you have already realised gains above £3,000 this tax year, you will need to report and pay CGT, either through Self Assessment or HMRC’s real-time CGT reporting service.
Who this applies to
Anyone who has sold shares, investment funds, a second property, or other chargeable assets this tax year. Spouses and civil partners each hold their own £3,000 exempt amount, and transfers of assets between them are exempt from CGT entirely, which creates useful planning flexibility for couples.
The £500 dividend allowance
The dividend allowance for 2025/26 is £500. Dividends received above this figure are taxed at:
- 8.75% for basic rate taxpayers
- 33.75% for higher-rate taxpayers
- 39.35% for additional rate taxpayers
Why this matters for company directors
For limited company directors who take income as a combination of salary and dividends, using the dividend allowance before 5 April ensures you are not leaving tax-free income on the table. If you have distributable profits in the company and have not yet drawn a dividend this tax year, doing so before 5 April uses the current year’s allowance.
Whether this is the right move depends on your overall income position for the year, so it is worth confirming the figures with your accountant before acting. Our guide on the best way to pay yourself from the company sets out the practical considerations around salary and dividend structures in more detail.
Who this applies to
Company directors drawing dividends and individuals with shareholdings in companies that pay dividends. If you have not received any dividends yet this tax year, the allowance is still available in full.
Marriage Allowance: transferring £1,260 of unused Personal Allowance
If one partner earns below the Personal Allowance threshold of £12,570 and the other is a basic rate taxpayer, the lower earner can transfer £1,260 of their unused Personal Allowance to their partner. This reduces the higher earner’s tax bill by up to £252 for the year.
Backdating the claim
Claims can be backdated up to four tax years, which means you could reclaim Marriage Allowance going back to 2021/22 alongside your 2025/26 claim. The total backdated saving could be over £1,000 depending on how many years are eligible.
Who this applies to
Married couples and civil partners where:
- One partner earns under £12,570 (and is not using another form of Personal Allowance transfer)
- The other partner earns between £12,571 and £50,270, placing them in the basic rate band
Marriage Allowance is not available to unmarried couples. Claims are made directly through HMRC, take only a few minutes, and the reduction is applied to the tax code automatically going forward.
Voluntary National Insurance contributions: do not miss your window
Gaps in your National Insurance record reduce your State Pension entitlement. You need 35 qualifying years for the full new State Pension, and some people have gaps from periods of self-employment with low profits, time outside the workforce, or years spent caring for family.
Checking your record
You can view your National Insurance record and State Pension forecast on GOV.UK. This shows you how many qualifying years you have, any gaps, and an estimate of what your State Pension will be at retirement. If gaps exist, you may be able to fill them with voluntary Class 3 contributions, currently priced at £824.20 per missing year.
The return in additional State Pension income over retirement typically makes voluntary contributions one of the best guaranteed returns available to individuals in the UK.
Who this applies to
- Anyone aged 45 or over who is approaching retirement and wants to maximise their State Pension
- Self-employed individuals who have had years of low earnings below the Lower Profits Limit
- Those who took time out of work to care for children or family members and did not claim National Insurance credits
- People who have lived or worked abroad for extended periods
If you are close to retirement and have gaps in your record, getting this reviewed before 5 April is particularly important, as HMRC’s rules on which years you can fill and at what rate do change.
Self Assessment: keep your records in order now
If you are self-employed, a landlord, a company director, or have income above certain thresholds that is not taxed at source, you will be completing a Self Assessment tax return for the 2025/26 tax year. That return covers income and gains arising between 6 April 2025 and 5 April 2026.
Keeping your records current now means the return is straightforward when the online filing window opens. Our checklist on the complete Self Assessment tax return outlines exactly what you will need to gather, from employment income and P60s through to rental statements and investment records.
Wrapping up
Every allowance on this list has a hard cut-off at 5 April 2026. ISA contributions made on 6 April automatically fall into next year’s allowance. Pension contributions that straddle the tax year boundary may be allocated to the wrong period. Marriage Allowance transfers and dividend decisions all need to be in place before 5 April to count for 2025/26.
The actions themselves are not complicated, but what stops most people is not knowing which ones apply to their specific situation, or not having the right figures in front of them to make confident decisions. That is where working with a qualified accountant makes a genuine difference, not just at year end, but as part of a longer-term approach that ensures you are never leaving allowances on the table.
eAccounts works with individuals, limited company directors, landlords, and self-employed clients across the UK. If you want a straightforward review of your year-end position before the deadline, our Chartered Accountants can turn this around quickly. Call us on 029 2105 5592, get an instant quote online, or find your nearest accountant near you to get started.
