Millions of Brits could lose thousands of pounds in pension tax relief within weeks if they fail to act before the April 5 2026 tax deadline.
Financial experts say the same mistakes happen every March, with savers leaving contributions too late or missing allowances that could significantly boost their retirement savings.
With the tax year ending on April 5, pension provider Penfold says acting now could significantly boost retirement savings while reducing tax bills.
Chris Eastwood, CEO and co-founder of Penfold, said many savers do not realise how much money they are leaving behind.
"We see the same mistakes every year. Most are easy to fix, but only if people act before the tax-year window closes."
The five pension mistakes experts say cost savers thousands
1. Assuming the tax deadline does not apply to you
Many people believe tax-year planning is mainly for business owners or high earners.
In reality, most people can receive tax relief on pension contributions up to the amount they earn each year until the age of 75.
This means the government effectively boosts pension contributions through tax relief.
Experts say failing to use this allowance means missing out on what is effectively free money.
2. Leaving pension contributions too late
One of the most common mistakes is waiting until the final days of the tax year to contribute.
But a payment made on April 4 does not guarantee it will reach the pension provider before midnight on April 5.
If it arrives late, the contribution counts towards next year instead.
Experts say this small timing issue can cost savers valuable tax relief.
3. Forgetting unused allowances can be carried forward
Many people also overlook the carry forward rule.
This allows unused pension allowances from the previous three tax years to be used in the current year.
However, allowances expire.
After April 5, any unused allowance from the 2022 to 2023 tax year disappears permanently.
That means missing the deadline could prevent savers from making larger contributions that attract tax relief.
4. Ignoring the £100,000 tax trap
One of the most expensive quirks in the UK tax system affects people earning more than £100,000.
Between £100,000 and £125,140 the personal allowance is gradually removed.
This creates an effective 60 percent tax rate on that slice of income.
However, pension contributions can reduce adjusted net income.
This means contributing to a pension before the tax deadline can bring income back below the threshold and restore some of the lost personal allowance.
5. Forgetting pensions are not just for workers
Many families are unaware that non-earning partners or even children can receive pension contributions with tax relief.
Up to £2,880 can be paid into their pension each year.
HMRC then tops it up to £3,600.
Experts say this is one of the most overlooked ways to build long-term retirement wealth.
How much you could lose by missing the deadline
Experts say failing to review pension contributions could cost savers significant sums.
For example:
- A basic rate taxpayer contributing £800 receives a £200 tax top-up
- A higher rate taxpayer contributing £10,000 could reclaim £2,000 in additional tax relief
- High earners caught in the £100k tax trap could potentially recover thousands by contributing before April 5
Small decisions made before the tax year ends can therefore have a major impact on retirement savings.
Quick pension deadline checklist
Before April 5 check:
- Have you used your full pension allowance?
- Could you carry forward unused allowances?
- Are you affected by the £100,000 tax trap?
- Will your contribution arrive before the deadline?
- Could you contribute to a partner or child’s pension?
The wider retirement savings problem
Research from Scottish Widows shows women face a 32 percent gender pension gap, leaving many with far less income in retirement.
Susan Hope, retirement expert at the company, said career breaks and caring responsibilities often reduce women's retirement savings.
"The gender pension gap is not just a statistic," she says.
"It directly affects the financial security many women experience later in life."
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Simple checks that could boost your pension by £250,000
Investment specialist Antonia Medlicott of Investing Insiders says reviewing pension funds regularly can dramatically improve long-term returns.
Checking fees, reviewing risk levels and ensuring investments are performing well can make a large difference over decades.
"For someone investing £2,700 a year into their pension, taking these steps could add around £257,000 to their retirement fund over 37 years," she said.
Financial specialists say the most important step is simply reviewing your pension before the tax-year window closes.
Check your contributions, confirm payments will clear before April 5 and make sure you are using available allowances.
Eastwood said the opportunity should not be ignored: "The allowances are generous and the relief is there. The key is acting before the deadline passes."
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