5.5 Gross Pay to Net Pay: Calculation, Reconciliation & Payslips

5.5 Gross Pay to Net Pay: Calculation, Reconciliation & Payslips

This is the calculation the AAT scope of content actually asks you to perform. Criterion 4.1.11 requires you to be able to calculate gross pay, taxable gross pay, deductions from employee pay, net pay, and the amount due to HMRC, and criterion 4.1.12 requires you to reconcile gross pay to net pay and to taxable gross pay. Crucially, there is a stated exclusion: the calculation of income tax, National Insurance contributions and student loan repayments is not assessed — those figures are given to you. What is assessed is whether you can assemble them into a correct payroll.

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1. Four Different Meanings of "Pay"

Getting these four apart is most of the battle.

The one that trips people up

National Insurance is charged on gross pay, not taxable gross pay. A net pay arrangement pension contribution reduces the figure income tax is charged on, but it does not reduce the figure NIC is charged on. Only a formal salary sacrifice reduces both, because it reduces contractual gross pay itself.

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2. The Gross-to-Net Sequence

  Basic pay + overtime + bonus + commission + statutory payments
                          │
                          ▼
                    GROSS PAY  ────────────────► base for employee & employer NIC
                          │
         less: net pay arrangement pension, payroll giving
                          │
                          ▼
                 TAXABLE GROSS PAY  ───────────► base for PAYE income tax
                          │
         less: PAYE income tax
         less: employee Class 1 NIC (calculated on gross)
         less: student loan / postgraduate loan
         less: attachment of earnings order
         less: voluntary deductions (union dues, healthcare)
         plus: non-taxable additions (expense reimbursements)
                          │
                          ▼
                       NET PAY

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3. Worked Example: One Employee, One Month

Scenario: Rowan is paid monthly. For June 2026 the payroll system reports:

Step 1 — Gross pay $£3,200.00 + £340.00 + £500.00 = \mathbf{£4,040.00}$ The mileage reimbursement at the approved rate is not pay; it is an expense reimbursement and stays out of gross pay.

Step 2 — Pension contribution $£4,040.00 \times 5\% = £202.00$

Step 3 — Taxable gross pay $£4,040.00 - £202.00 = \mathbf{£3,838.00}$ This is the figure PAYE is charged on. The employee NIC of £249.00 was calculated on the £4,040.00 gross figure, not on £3,838.00.

Step 4 — Net pay

Step 5 — Amount due to HMRC for this employee

The pension contribution and the union subscription are not paid to HMRC — they go to the pension provider and the union respectively. That is a very common error.

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4. Reconciling Gross to Net

The reconciliation is the control that proves the payroll balances. At employee level:

$\text{Gross pay} = \text{Net pay} + \text{Total employee deductions} - \text{Non-taxable additions}$

Checking Rowan's figures: $£3,037.50 + (£202.00 + £552.40 + £249.00 + £71.00 + £14.50) - £86.40 = £4,040.00 \;\checkmark$

At payroll level, three separate totals must agree:

A difference means one of four things: an employee added or removed after the run, a manual adjustment posted outside the payroll, a statutory recovery claimed on the EPS but not journalled, or a genuine calculation error. Section 6.2 covers the journals; the point here is that the reconciliation must be performed before the FPS is sent, because the FPS is a legal declaration.

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5. Payslips

Every employee is entitled to an itemised payslip on or before payday. It may be paper or electronic. It must show:

1. Gross pay for the period.
2. The amount and purpose of every variable deduction — income tax, NIC, student loan, attachment of earnings.
3. Fixed deductions, either itemised or as a total supported by a standing statement issued at least annually.
4. Net pay.
5. Where pay varies with hours worked, the number of hours paid.
6. The method of payment, if more than one method is used.

Good practice, though not strictly required, adds the tax code, the NIC category letter, the pay date, and year-to-date figures for gross pay, tax and NIC — all of which help the employee spot an error early.

⚠️ EXAM TRAP: Employer's National Insurance is a cost to the business, not a deduction from the employee. It should never reduce net pay, and while many payslips show it for information, it never appears in the deductions column.

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6. Non-Statutory Deductions and Consent

Statutory deductions — income tax, employee NIC, student loan repayments and attachment of earnings orders — are made without the employee's separate consent, because legislation or a court order requires them.

Everything else is a non-statutory deduction and requires prior written authorisation under the Employment Rights Act 1996, or a term in the contract of employment. Typical examples are voluntary pension top-ups, trade union subscriptions, payroll giving, season ticket loan repayments, private healthcare and staff purchase schemes. Deducting from wages without that authority is an unlawful deduction, regardless of how reasonable the amount seems.