Employment tax deductions and relief

A deduction is different from a cash refund

Eligible employment expenses may reduce the income on which tax is charged. A £100 deduction is not a £100 payment: the benefit depends on the tax actually saved and the applicable conditions.

Some allowances operate differently. Marriage Allowance is a tax reduction for an eligible recipient, limited by their tax liability; the transferring partner may pay extra tax.

Work expenses must meet the rules

Check whether an expense qualifies, whether your employer reimbursed it, and what evidence HMRC requires. Professional subscriptions must meet HMRC’s conditions; ordinary clothing and commuting do not become deductible simply because they relate to work.

The appropriate claim route and time limit depend on the expense and circumstances. A small expense claim does not by itself establish that you have no other Self Assessment obligation.

Pension arrangements differ

The main calculator models salary sacrifice, which can reduce contractual pay used for Income Tax and NI. A net-pay pension normally reduces Income Tax pay but not employee NI. Relief at source has another mechanism.

Use the pension tool to compare the supported methods. Check contribution limits, minimum-wage restrictions and your employer’s terms before changing arrangements.

Sources and next steps

• HMRC employment-expense guidance
• Marriage Allowance
• Compare pension deduction methods
• Marriage Allowance estimate

Reviewed 22 October 2026 by the AfterTaxUK Editorial Team. Check the applicable year and circumstances before relying on an estimate.