Free New Zealand calculator
Back Pay Calculator NZ: Estimate Gross Wages Owed
Calculate straightforward gross back pay after an underpaid hourly rate or a missed gross payment across a chosen number of pay periods.
Calculation sources checked 11 October 2026 · NZD · Estimates only
How does it work?
For an hourly rate correction, multiply (correct hourly rate minus amount paid per hour) by the affected hours per period, then by the number of periods. Missed gross amounts can be entered directly.
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Your estimate
Method and worked New Zealand example
Rate correction: (corrected gross hourly rate − original gross hourly rate) × eligible hours in each period × the number of periods. Use this only when the same hours and rate difference apply to every period.
Example: a change from $28 to $30 for 40 affected hours in each of three pay periods = $2 × 40 × 3 = $240 gross. For a missed fixed gross amount, enter that amount and the number of periods instead. For variable rosters, calculate each distinct period separately and add the totals yourself.
Assumptions and important limitations
Not a full employment-entitlement or payroll remediation calculation. Excludes PAYE and ACC withholding, KiwiSaver, overtime multipliers, holiday-pay remediation, penalty rates, interest and disputed classifications. Back pay may be subject to IRD lump-sum withholding; do not interpret gross as take-home.
Official sources (checked 11 October 2026): IRD lump sum payment calculations; Employment NZ pay and wages.
Frequently asked questions
Is this net back pay?
No, results are gross before withholding and deductions.
Can I calculate missed salary?
If you know the missed gross amount per pay period, choose Missed gross payment.
What if my hours varied?
Calculate each pay period separately and add the results; do not use an averaged period when it obscures actual hours.