You do not need to be an accountant to find out whether you have been underpaid. You need three things: the rules that set your pay, a record of the hours you worked, and a record of what you were paid. This guide walks you through the calculation the way a court or the Fair Work Ombudsman would do it. If you get stuck, we can do it for you.
The core idea. An underpayment is the difference between what you were entitled to and what you were actually paid, worked out pay period by pay period, using the rates in force at the time you did the work.
Step 1: Work Out Which System And Which Rules Apply
First, check whether you are in the national (Fair Work) system or the WA state system. Most people who work for a company (a Pty Ltd) are in the national system under the Fair Work Act 2009 (Cth). Employees of sole traders, partnerships, trusts run by individuals, WA local councils and the WA public sector are usually in the WA state system. See Am I in the state or federal system?.
Then find the instrument that sets your minimum pay. In the national system it will be one of these:
- A registered enterprise agreement, if one covers your workplace. It replaces the award while it applies to you, but it cannot give you less than the National Employment Standards.
- A modern award, if no enterprise agreement applies. Most jobs are covered by an award, based on the industry and the kind of work you do. The Fair Work Ombudsman's Pay and Conditions Tool and its list of awards will help you find yours, and our simplified awards explain the common ones in plain English.
- The national minimum wage, if no award or agreement covers you (you are "award-free"). From 1 July 2026 it is $26.44 an hour, or $1,004.90 for a 38-hour week ($24.95 an hour from 1 July 2025). Casual award-free employees get a 25% loading on top, which is $33.05 an hour from 1 July 2026.
Your employment contract sits on top of these. It can give you more than the minimum, but never less.
Step 2: Find Your Classification
Awards and agreements set different rates for different levels of work, called classifications. Your classification depends on what you actually do, your skills and qualifications, and sometimes how long you have been doing it, not on your job title. Read the classification definitions in the award and pick the one that best matches your real duties.
Classification is one of the most common sources of underpayment, especially where your duties grew over time but your pay did not.
Step 3: Get The Rates For Each Period
Minimum rates change every year from 1 July, when the Fair Work Commission's Annual Wage Review takes effect. From 1 July 2026, modern award minimum rates rose by 4.75% and the national minimum wage by 6.0%. So for each period of your claim, you need the rates that applied then.
The Fair Work Ombudsman publishes a pay guide for every award, and the Pay and Conditions Tool lets you choose the date you want the rates "as at". For each period, note:
- the base hourly rate for your classification (or the junior, apprentice or trainee rate, if that applies);
- the casual loading or casual rate, if you are a casual;
- penalty rates for evenings, nights, weekends and public holidays;
- overtime rates, and when overtime starts (after so many hours a day or week, outside the span of ordinary hours, or on a rostered day off);
- allowances that apply to you (for example tools, uniform, laundry, meals, vehicle or travel, first aid, higher duties);
- leave loading on annual leave, if your award provides for it;
- the superannuation guarantee rate: 12% from 1 July 2025 (11.5% in 2024-25).
Step 4: Rebuild Your Hours
For each pay period, work out the days and hours you worked, including when you started and finished and any unpaid breaks. Use everything you have:
- rosters, timesheets, clock-in records and app records;
- pay slips and bank statements;
- text messages, emails and group chats about shifts;
- your own diary or calendar, or the Fair Work Ombudsman's Record My Hours app.
If you do not have exact records, a reasonable reconstruction of your usual pattern is still evidence. And if your employer failed to keep the records or give you the pay slips the law requires, then in a court claim it may have to disprove what you say about your hours and pay (s 557C of the Fair Work Act), unless it has a reasonable excuse.
Step 5: Calculate What You Should Have Been Paid
For each pay period, multiply each block of hours by the rate that applies to it. Keep the categories separate, because the award usually treats them differently:
| Hours | Rate to apply |
|---|---|
| Ordinary hours, Monday to Friday | Base rate (plus casual loading if you are a casual) |
| Evening or night hours | Base rate plus the award's evening or night penalty |
| Saturday and Sunday hours | The award's weekend rate |
| Public holiday hours | The award's public holiday rate |
| Overtime | The award's overtime rate, from the point overtime starts |
| Allowances | Per shift, per week or per kilometre, as the award says |
Then add superannuation on the eligible earnings, and any leave that was not paid, or not paid at the right rate. If your job has ended, check whether untaken annual leave (and leave loading, if your award says it is paid on termination) and any long service leave were paid out.
Step 6: Compare And Total The Shortfall
Subtract what you were actually paid in each pay period (the gross amount, before tax) from what you should have been paid. Add up the shortfalls across all periods. That total, plus unpaid super and interest, is your claim.
Watch the time limit. A court claim under the Fair Work Act must be made within 6 years after each contravention (s 544). Each pay period is a separate contravention, so the oldest part of your claim expires month by month. The same 6-year limit applies to WA state system claims in the Industrial Magistrates Court (s 82A of the Industrial Relations Act 1979 (WA)).
Common Traps
- "But I'm on a salary." A salary can still underpay you if it does not cover the award rate for all the hours you actually work, including overtime and penalty rates. Whether an above-award salary can be counted against those amounts depends on what the payment was for under your contract, and the law on this is currently being tested on appeal. Get advice before assuming either way.
- "I'm a casual, so I don't get penalty rates." Casuals usually get both the casual loading and penalty rates under their award. How the two combine differs from award to award.
- "I'm a contractor." If the real substance of your arrangement is employment, you are an employee whatever the contract calls you. See our page on contractors.
- Unpaid trials, training and meetings. Time you are required to spend working, training or attending meetings is usually paid work.
- Deductions. Your employer can deduct money from your pay only in limited cases, such as with your written authorisation for a deduction that is principally for your benefit (s 324).
- Using today's rates for old periods. Always use the rate that applied when you did the work.
WA State System Employees
If you are in the WA state system, the same method applies, but the rules come from your WA award or industrial agreement and the Minimum Conditions of Employment Act 1993 (WA). The State Minimum Wage for award-free adults is $998.30 a week ($26.27 an hour) from the first pay period on or after 1 July 2026 ($953.00 a week before that), with a 25% casual loading. Claims are enforced in the Industrial Magistrates Court. See minimum conditions in the WA state system and underpayments in the WA state system.
What To Do Next
Once you have a figure, see I've Been Underpaid for how to recover it: a letter of demand, the Fair Work Ombudsman, the small claims procedure (for amounts up to $100,000) or a court claim.
Calculations can get complicated quickly, particularly across several years, several awards or several classifications. If you would like us to check your figures or do the calculation for you, contact us for a free confidential discussion.