How do I calculate total underpayment across multiple pay periods?

For each pay period, work out what you SHOULD have been paid (hours × correct hourly rate, including any penalty rates and allowances) and subtract what you ACTUALLY received. Add up the shortfalls across all periods, then add pre-judgment interest from each period's end date to today. This tool does the entire calculation including statutory interest and outputs a Statement of Claim PDF.

Can I claim interest on underpaid wages in Australia?

Yes. Section 547 of the Fair Work Act 2009 allows the Federal Circuit and Family Court of Australia to award pre-judgment interest on unpaid wages. The court typically calculates this at the RBA cash rate plus a margin (often 4-6%), simple interest, from the date each underpayment occurred to the date of judgment. This tool uses 10% per annum simple interest as a reasonable indicative rate.

How far back can I claim underpaid wages?

Up to 6 years from the date the underpayment occurred, under section 544 of the Fair Work Act 2009. Periods older than 6 years are statute-barred and cannot be recovered through the courts. This tool flags any period older than 6 years as a warning. The 6-year clock runs separately for each pay period — so periods within the last 6 years remain claimable even if older periods are barred.

Where do I lodge an underpayment claim?

Two main pathways: (1) The Fair Work Ombudsman (13 13 94 / fairwork.gov.au) can investigate and recover wages without you needing a lawyer — free. They are the first port of call for most workers. (2) The Federal Circuit and Family Court of Australia for formal court action (small claims jurisdiction available for claims up to $20,000). The PDF generated by this tool can be used to support either pathway.

What if my employer claims they made an honest mistake?

Honest mistake or not, the underpayment must be repaid. Civil penalties under s546 of the Fair Work Act may still apply, but courts and the Fair Work Ombudsman can take an honest mistake into account when deciding penalty amounts. Either way, you are entitled to the back-pay plus interest on the period the money was withheld.

Underpayment Claim Builder

Add up underpayment across multiple pay periods, calculate pre-judgment interest, and download a Statement of Claim PDF. The only free Australian tool that aggregates back-pay claims with interest properly modelled.

Last verified: 2 August 2026

Your details

Your name

Your address

Employer name

Employer address

Modern Award or EA name (optional)

Your classification (optional)

Pay periods

For each pay period, enter the period end date, hours, what you were paid, and either what you SHOULD have been paid (gross) OR the correct hourly rate. The tool computes shortfall and interest.

Period 1

Period end

Hours

Paid (AUD)

Owed (AUD)

OR — correct hourly rate

Note (optional)

Period 2

Period end

Hours

Paid (AUD)

Owed (AUD)

OR — correct hourly rate

Note (optional)

Period 3

Period end

Hours

Paid (AUD)

Owed (AUD)

OR — correct hourly rate

Note (optional)

How this works

• Shortfall per period = what you should have been paid minus what you were actually paid.
• Interest at 10% per annum simple interest, on each period's shortfall, from period-end-date to today. This is a reasonable proxy for the courts' pre-judgment interest awards under s547 of the Fair Work Act 2009.
• Six-year limitation: section 544 of the Fair Work Act bars claims older than 6 years. Periods older than that are flagged but excluded from the formal claim.
• The PDF is a draft Statement of Claim — not legal advice. Most workers should call the Fair Work Ombudsman (13 13 94) first — they can recover wages without you needing a lawyer.

Useful links

→ Quick Underpayment Check (single rate)→ Underpayment Enquiry Letter → EA Finder + Comparator → Fair Work Ombudsman — Wage theft & underpayments

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General information and estimates only — not legal, financial or tax advice. Always check your specific award, agreement or contract, or a qualified professional, before you rely on the result.

Underpayment Claim Builder

Your details

Pay periods

How this works

Useful links

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