Pension deduction checker (UK)

The problem

Pension deductions are one of the most misunderstood lines on a UK payslip. The same percentage contribution can produce a very different net-pay outcome depending on whether your scheme is net-pay, relief-at-source, or salary sacrifice.

A frequent issue is being told "your contribution is 5%" but seeing a number on the payslip that does not match what you expected - usually because the calculation base (qualifying earnings vs. full salary) or the scheme type is different from what you assumed.

Plain-English explanation

There are three UK workplace pension setups in use today:

• Net-pay arrangement - your contribution is taken before income tax. Your taxable pay drops by the contribution; you get tax relief at your marginal rate automatically. NI is unaffected.
• Relief-at-source (RAS) - your contribution is taken from your post-tax salary, then HMRC adds 20% back into your pension pot. Higher-rate taxpayers must claim the extra relief themselves via Self Assessment or HMRC.
• Salary sacrifice - you contractually give up part of your salary in exchange for an employer pension contribution. Your taxable pay AND your NI-able pay both drop, so you save income tax and NI.

Most contributions are calculated on either qualifying earnings (the band between £6,240 and £50,270 for 2026/27) or pensionable salary (a definition set in your scheme rules). The difference between the two can be significant.

Worked example - 5% contribution on £36,000, three setups

Worked example uses 2026/27 UK figures and is illustrative. Do not use it as a personal tax calculation.

Step by step

1. 1

   Identify the scheme type

   Look for a "salary sacrifice" or "smart pay" line on your payslip - this signals salary sacrifice. Otherwise, ask payroll whether your scheme is net-pay or relief-at-source.

2. 2

   Identify the calculation base

   Ask payroll what the percentage is calculated on: qualifying earnings (£6,240–£50,270 band), pensionable pay, or full salary.

3. 3

   Recalculate the contribution

   Apply the percentage to the calculation base for the period (annual figure ÷ 12 for monthly pay). Compare with the deduction line on your payslip.

4. 4

   Check the tax effect

   For net-pay and salary sacrifice, your taxable pay should drop by the contribution. For relief-at-source, taxable pay is unchanged.

5. 5

   If you are a higher-rate taxpayer on RAS, claim extra relief

   HMRC adds basic-rate relief automatically. You must claim the additional relief yourself via Self Assessment, your tax account, or by writing to HMRC.

6. 6

   Run a free PayslipIQ check

   Upload your redacted payslip and PayslipIQ will identify the most likely scheme type and reconcile the maths.

What to ask payroll

• ?Which pension scheme type am I in - net-pay, relief-at-source or salary sacrifice?
• ?What earnings does the contribution percentage apply to - qualifying earnings, pensionable pay, or full salary?
• ?What is the employer contribution rate on top of mine?
• ?If I increase my contribution, will it come out of net pay or before tax?
• ?Can you confirm the auto-enrolment status on my account is "active" rather than "opted out"?

When to contact HMRC

• For net-pay and salary sacrifice setups, no HMRC action is needed - the relief is automatic.
• For relief-at-source schemes, HMRC adds basic-rate relief direct to the pension. Higher-rate taxpayers should claim the additional relief via the personal tax account or Self Assessment.
• If you are concerned about exceeding the annual allowance (£60,000 in 2026/27 for most people), check pension input amounts across all schemes via your scheme administrators and consider taking pensions advice.
• PayslipIQ does not advise on pension transfers, contribution-rate changes or annual allowance strategy. For those, speak to a regulated financial adviser.

FAQ

Why does my pension deduction look different to my colleague's?

Likely scheme type or calculation base. A 5% net-pay contribution and a 5% salary-sacrifice contribution land on the payslip the same way, but the tax effect differs. Two colleagues on the same percentage with different pensionable-pay definitions will see different cash deductions.

Should my pension reduce my tax?

Yes for net-pay arrangements and salary-sacrifice schemes. No for relief-at-source schemes - your taxable pay is unchanged, and the tax relief is added directly to your pension pot.

Does pension deduction reduce my National Insurance?

Only under salary sacrifice. Net-pay and relief-at-source arrangements do not reduce NI-able pay.

I am a higher-rate taxpayer - am I getting the extra tax relief?

In a net-pay arrangement, yes - automatically. In a salary-sacrifice scheme, yes - automatically. In a relief-at-source scheme, no - you must claim the extra relief yourself via Self Assessment or your HMRC personal tax account.

Is PayslipIQ a regulated pensions adviser?

No. PayslipIQ provides educational explanations only. For decisions on contribution rates, transfers, annual-allowance planning or retirement income, speak to a regulated financial adviser.

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